Boss GT-3

I haven't touched my ME-30 or my AX1G since I bought the GT-3. The people who will get the most out ot the GT-3 are serious musicians. It has a _LOT_ of features which makes it not as simple as, say, the AX1G. But, the effort you put into learning the box will pay off the first time you wail on it in public.
For a quick easy setting to impress your friends, set it to Bank 1, patch 4 (Auto Riff) and check out how easy it is to sound like you are ripping off lightning fast hammer ons and offs ala Steve Vai.

I jack my Ibanez JS-100 thru a BadHorsey wah pedal to the GT-3. I run the GT-3's stereo L and R to my two combo amps (1 ReverbRocket and 1 Crate GFX).

I have tried DI-ing the GT-3 directly into my PC using CakeWalk to do multi-track digital audio recordings. No problems so far. The Noise Level is certainly lower than with my ME-30 or AX1G.
I have had no problems at all doing MIDI dumps, but from comments I read on alt.guitar.effects, my advice for MIDI users is to use MIDI software which someone else has already verified works with the GT-3.

I have bought Boss and Roland products for years. I have never had one die on me and this one is built like a Sherman tank. I did have my local Roland dealer (Sam Ash) contact Roland about the MIDI Implementation Manual mentioned in the user's manual. I got a response back in a couple of days telling me the manual hadn't made it out of Japan wasn't out yet but will be free for download when available. For now, use the MIDI chart towards the end of the user's manual.

I play jazz-rock fusion. The GT-3 has an unbelievable 340 patches from the factory which allows me to pretty easily bounce back and forth from Ritenour rhythms to Satch leads. You can effectively consider it to have unlimited patch capability since you can store and write as many patches as you like to your PC thru the MIDI interface. I would be surprised if a GT-3 plug-in doesn't show up soon to allow you to control it from CakeWalk's Guitar Studio software. I honestly expect this box to become the industry standard for multi-effects pedals.

Everything works as expected. I've look at the manual just a few times. For everything this thing does, it's laid out clearly and simply. Because it can do so much, there is a certain amount of complexity. There's an EZ edit mode which I havn't used much, but it could be handy for last minute, onstage changes.

The key to this thing is to build your own sounds from the ground up. Ignore the presets! They're generally mediocre (too much reverb, delay and compression).
I use this with a Parker Nitefly direct into the PA. With this $1400 dollar setup, I can nail 90% of all known guitar sounds. This thing is that good and versatile. The virtual "amps" are distinct and a lot of fun to play around with. The Marshall sounds a little dark, and the Blues & 5150 sound ugly to me, but everything else is useful. The Mesa Boogie preamp is my favorite for "everyday" sounds. It also includes all the basic distortion "pedals". You can set up a "clean amp" with a pedal, or an overdriven amp, or a combination of both. It also includes Boss's new 2X2 chorus, which lets you divide up the chorus according to frequency. It also has an acoustic preamp, which minimizes harsh piezo "quack" when you hammer on an acoustic.
Almost Every effect is good sounding and useful, providing you dig in and adjust to taste. Some of the "distortion pedals" are pretty buzzy, but that's how some "real" pedals are. The comp/limiter is great on clean sounds, but there is no ratio control. The modulation effects are also great.
Boss did include some junk, as usual. The artificial feedbacker and auto phrase are profoundly cheesy. The synth stuff ain't much better. Another gripe is there's no dedicated foot pedal for tuning/muting. You can assign the control or expression pedal for this, but this is limiting. Also, Boss should give up on the "acoustic simulator" stuff. No one is going to be fooled.

As a former ME-30 user, this thing is reassuringly solid. Plus, who can fault the Boss reputation?

I'm the music director at a church and we play any and every style (recent artists we've covered: Alabama, Everclear, Goo Goo Dolls, Jim Croce, Alanis Morrisette, Paula Cole, Joe Satrioni). This thing covers it all easily. If you need versatility, this is the best I've tried. At under $400, it's an excellant value (only $150 more than the ME30!)
One cool thing is the control pedal, which can affect any parameter. I have it set up to boost my volume 4 db so when I solo, I don't have to depend on the soundman turning me up.
To sum up: buy it.