I've got the GT-8 and my friend has a POD XT...the POD XT is very impressive, but so is the GT-8 for that matter. I prefer the GT-8's onboard effects to the XT Live's because the POD sounds somewhat digital to me. The sound is quite good, but it still doesn't sound REAL...this is just my opinion. The GT-8, however, sounds just like any other amp if you put it through your head. I recorded a demo with it and it sounded better than the Marshall, actually. Now I use it only for effects, no distortion whatsoever. All my distortion comes from my Peavey 6505+ head, only I run the 4 cable method with the GT-8, activating only the EQ and Compressor and a little Reverb since the head doesn't have any reverb on it. I don't use any boost or anything anymore since I got that head...the GT-8 now is set up like a bank of stompboxes all in a row...Chorus, Flanger, Delay, Reverb, etc. You can use the stompboxes in conjunction with your head, but if you've got a high gain head, I wouldn't use anything more than a Tubescreamer stompbox setting coupled with EQ and maybe compressor. Personally, I don't need any more distortion, as I value tone over complete face melting distortion.
I bypass the amp head when with the 4 cable method I want to go with a clean sound because Peavey's cleans suck ass. I have a preset for several cleans and other weird effects, along with my distortion setup. I change patches like any other multifx, only when I need to get back into the distortion, I hit the CTRL button, which basically locks you into a different setting of the same preset, utilizing the other patch BUTTONS for "stompbox effects". In English, patch button 1, 2, 3, and 4 are changed when you hit the CTRL button, and it kinda "locks" the patch in MANUAL mode...when it's in manual mode, you can set MANUALLY the patch buttons how you want...whether they become patches or other effects within the same patch is up to you. Just try it out and you'll see...
You can also download patches from
www.bossgtcentral.com on your PC, then upload it via MIDI to your GT-8. You can do this with the POD as well, and I think even the POD has a USB port. BossGTCentral.com is a third party forum, so we just post our patches and then upload them to the GT-8. You can also do this with all the GTs.
It all depends on what you need it for. I use my GT-8 as an effects board AND rack system, as it has everything you need. I've even got a G Major rack system that I don't even use because I like the GT-8 better. It's got every single thing you ever need in one package, and it sounds fucking great too. However, THIS ISN'T THE DIGITECH MULTIFX PEDAL!!!!! The Digitech pedals are really good and sound really good, but there is a limit to how much you can tweak in them. There is no limit to the GT-8, and that is also it's downfall. The learning curve is quite steep on it, and I've had it for about a year and I'm still only scratching the surface. There's still tons of things that I don't know about it. You can also rearrange the FX chain for each patch, getting different sounds out of different orders. For instance, put the distortion and wah behind the amp instead of in front of it and it sounds completely different. If you wanna learn more about it, go to the bossgtcentral website. The people there are very, very, very nice and will bend over backwards to help you.