well i've had the GT-Pro for a couple of days and I must say I like it a lot so far. in my opinion it doesn't color the sound too much, unless you use an insane amount of effects at one time. some people said it just murders your tone and they didn't like it because of that, so i was pleasantly surprised to find out it doesn't do that to my sound. i bought it mainly for chorus , delay, and reverb and it does a great job with all three, just as good if not better than my boss pedals. i've also tried out the phaser , flanger , ring modulator, tremolo, and compressor and they all sound good for a multi fx processor. i wish the compressor had a built in gate but there is a noise supressor you can use so its not a big issue. there are a few really cheesy effects that i'll never use, like the 'guitar synth' and sitar emulator. i haven't tried the amp control functions yet ( i have an axess electronics CFX4 for switching my mark iv channels through MIDI). I noticed there is a slight delay between changing patches if you go backwards (like from patch 10 to 1), but its not a big deal. i've only noticed it with certain patches so it might have something to do with how i have them configured. the patch editing / librarian software is very cool and makes editing your sounds very easy. I haven't used the amp modeling at all yet, but i will be using it when I record. i'm sure it will make a great preamp for direct recording. one thing i thought was odd about the gt pro is that the AC cord doesnt have a ground plug, its just a 2 prong delta plug. maybe they did that to cut down on noise? i noticed that the GT pro adds a little bit of operating noise to my signal, but i guess that's to be expected. all in all it does what i want it to do, it doesn't kill my tone, and it does the effects i use the most very well so i think i will keep it.