Ok, in case you don't know, the Line6 M13 is the latest in the line of effects modellers from Line 6 (though there is an M9 out now, basically the same with less features in a smaller box). It incorporates all the modellers previously made by Line 6 (DL4 Delays, DM4 distortion, JM4 Looper, MM4 Modulation and FM4 Filter - plus reverbs from the Verbzilla) - only they've improved them. If that wasn't enough, with the latest update they added over 16 new effects, including EQ's, Parametric EQ's etc etc etc
As far as looks go - someone said it was ugly, it's not its robust and practical - what can be more sexy than a big black box with a shitload of pushbuttons in chrome? Heres a pic next to some other pedals for scale:
and compared to the DL4 its positively beautiful.
Heres some of the company blurb
And they aren't wrong - its stupidly easy to use, just like normal stomboxes, you want more gain? Just turn the gain knob, more depth? yes the depth knob etc etc etc - once a model is assigned to the position on the board, just hit the footswitch and the top lcd for that column lights up showing which knob is assigned to what. It truly is a doddle. In normal mode, it autosaves too, so any changes you make are always saved (you can turn this off)Boasting over 100 distinctive distortions, velvety reverbs, juicy delays and more, M13 Stompbox Modeler gives you total tone control. Use up to four different effects - or four of the same - simultaneously. Stompbox-style knobs deliver on-the-fly tweaking.
Order the effects any way you want. Create different pedal board effect arrangements, or "scenes," to instantly recall an entire song's stompboxes. Save a scene for your metal band, one for your Top 40 gig…you get the picture. No more tearing up Velcro® just to change one or two pedals! Save up to 48 scenes and back them up to your computer using the MIDI in/out.
The 28-second looper is always at the ready with dedicated footswitches for Play/Stop, Half Speed, Reverse, Undo/Redo and more. Each metal footswitch can withstand constant stomping and rock and roll-style abuse.
Easy to use, built like a tank and sporting an on-board chromatic tuner, M13 Stompbox Modeler can maximize your pedal board (or even replace it) like no other pedal can.
Ok - LIKES:
Over 100 high quality effects (even some of the guys at thegearpage like them
) - its bloody expensive new, RRP is just under 1400 bucks though I'm sure the RS guys would cut you a deal - but that works out at $14 a pedal 
One of the new models is a Whammy that is as good as the Digitech I owned.the delays, reverbs, modulation stuff is stunning, absolutely brilliant. The Filters are great especially the Wah's - its worth getting an expression pedal just for those models
(and you can control lots of other great shit with it too, speeding up delays/phase/flange etc, and you can set it to control more than one effect at the same time) And don't forget you can use any combination of these, in any order - so you want 4 different delays on at once, do it!the overdrive/fuzz/distortion models I was fully prepared to be let down by, just in case they were fizzy and obviously digital. I would say they are pretty awesome too, just for the variety of pedals modeled and their sound and tone, they do take a bit more work to get to the point where they sound good and some of the parameters can be a bit misleading, but my screamer is relegated solely to backup duties now. They're all very useable, and sound great to my ears.
Bright leds above each button remind you what effect type is stored in that position, after that its down to memory
Did I mention it has two expression pedal inputs! That would be crazy
A new pedal a day for the next 100 days
Line 6 updates - they just added in over 16 new models including a script phaser, the ability to have an extra 32 scenes etc etc etc.
Its stereo
and its True Bypass (by switching relay, noisless as far as I can detect)The looper - apart from the good fun to be had ripping off KT Tunstall, its invaluable for tweaking your settings. Record a loop of you rythym, solo whatever, add the effects you want and tweak while it plays back. There it is all setup for you, no more playing a bit, bending over and adjusting the gain, playing a bit, fiddling with the EQ etc etc etc.
Easy to use - they weren't fecking kidding, its stupidly easy to use, I kind of miss delving into the manual every 15 minutes or so
I like lots of the other shit on here, too much to mention.
Ok, dislikes:
The price, I got mine 2nd hand from John T, thanks mate - its awesome
Though I'm sure Matt/Dave will cut you a deal.Its heavy - sturdiness comes with a price.
The tuner - yes its built in but I imagine its a bitch to see in daylight, but if you only plan to play on dimly lit stages - throw the pitchblack away.
Autosave - yep a godsend at times, a pain in the arse at others - you've got your patches sorted then you mess something up before you power down/switch scenes. Its there next time you switch back to that scene. You can turn this off and save stuff manually - you could also get your effects sorted then copy them somewhere that you never overwrite, but do you do PC backups?
Pedal order is defaulted from left to right - you can change the ordering though, for me I'm used to right to left, took me about 15 minutes to figure out thats why my delays sounded shit when I hit the distortion pedal
NO USB PORT - must have saved 50 bucks there fellas, it takes about 30 mins to load new firmware via midi, got to hope the cat doesn't pull the leads out. Back up anything you want to keep before you do a firmware upgrade, it all gets wiped.
The looper is mono - lots of great features and I guess if it was stereo the time would be halved to 15 seconds (30 seconds in the norm, or a minute in half speed mode) - minor quibble.
The addition of 32 more scenes sounds great, till you realise you actually have to bend over and twist a knob to access these - why not just put it on a different footswitch? hit the scene button then the tap tempo button within 2 seconds etc... would have been much more useable. The good thing is the product manager for the M13/M9 actually takes suggestions like this onboard - amazing
Most of these are minor quibbles really, and outweighed by the quality of this multi-effects box, its awesome just to know that I don't actually need to buy another pedal ever again
(though I'm sure I probably will lol)In conclusion and bearing in mind that I haven't scratched the surface of the possibilities with this modeller yet - apart from the price, which is a fair old wedge of cash, I wouldn't hesitate to recommend this to anyone, as for reliability I haven't read anything about major stuff (this has been out in the US for over a year now) and its got tons and tons of toys to play with - but thats what you'll end up doing, playing your guitar rather than trying to figure out how to select a delay with mod, and how to set it up. Shit, I've got a basic scene set up with compressor boost, overdrive, classic distortion (RAT), Fassel Wah, Trem, Univibe, 3 types of delay and 3 types of reverb - it took about 20 mins to set up and tune in how I like it. If you get one though - get/make an expression pedal (I converted my crybaby, anyone want to buy a hendrix wah board? ) its so much fun its probably illegal
and the M9 will be just as much fun in a smaller box and a lot less stomp switches
Pure awesome