Try a GT-8.
No...seriously.

Try the GT100 through a mixer. I'm of the firm belief the 10 is best through an amp, the 100 through a mixer. Boss NEVER make decent factory patches. See if you can get your 10 back.

I went to Guitar Center and it was sitting in the display case looking all perfect and ready for a trip back home but they offered to replace the GT-100 with a new one as I firmly believe something was wrong with it.
Well I got the new one back home and it sounds as it should. Nothing like the first one. This one was running version 1.05. So I did the full 2.3 update and this thing sounds pretty damn good.
I like the simpler way of setting it up.I think I'll get use to it. I'm so versed in the GT-10 that I'm tripping my way around it but it's more similar then different. Quicker I would add.

The Amp modelers which I don't use that much but like to fool around with sound a bit more analog. They are warmer in all regards.

I'll post a full review of the Gt-100 once I fully test drive it.

So after a week of tweaking and playing I can honestly say this is by far the very best GT model I have ever owned.
What really impressed me over the last week is first off the ability to retain almost all of my original amps tone. This is something I felt lacked in the GT-8 and GT-10. The GT-100 allows more of your tone to shine through.I'm gonna say about 95 to 97%. It's damn close to being transparent. I'm very happy about that and I can lose that much to gain so much more.

The OD pedal models are incredible and very organic sounding. I was going through them and finding myself laughing on how damn good they sound. I was putting them in front of my clean channel to get a nice clean boost and then going deeper and actually using them for some great rock and even 80's medal tones. I was tickled pink as the GT-10 didn't sound this good in this area. Such a plus as I even was able to Boost my Gain channel of my amp and really create a beautiful strong tone/tones. I'm so happy with this that I wish I would have picked this up the day it came out.

The downsides to this unit is still the built in preamps. I have not been able to dial in as good as tone as I was able with the GT-10. The Amp models do sound better in some way meaning they are warmer and sound a bit more natural but they are harder to dial in. I don't use them much but I have them so I like to play with them from time to time. This ihoneslfy is becoming less and less important to me as the OD pedals with my clean channel sound much better then all the mp models inside this unit. The new Bogner amp model sucks ass as it doesn't sound anything like a Bogner other then the gain structure. The actual response and clarity is just no where there. I think Boss screwed up when they designed it as it doesn't sound like any Bogner I have played. Not even close.
What I find sunny about that is the Marshal tones of the GT-10 where actually really close. I could dial in some AC DC tones with ease, some ZZ Top stuff at will and some really nice 80's hair metal band tones with no boost or anything just the modelers. On the GT-100 I have yet to get even close. But overtime I'm sure I'll figure out how to make them sound their best. Just right now none of the amp modelers are of any use to me. This is the part where I usually wish Boss would make a GT model with just effects and ditch the whole Modeling thing. The GT is an incredible unit especially when wired in the 4CM which is the only way it makes any sense.

Another thing I find tuff is getting the Delay's to sound like i did in the GT-10. The GT-10 had a tap tempo and this does not unless I don't know how to engage it. It also get this funny fizzy sound sometimes when running delay in the loop with my drive channel. I don't remember the GT-10 sounding like that. Again I think I need to spend more time dialing in a usuable Delay as for my cleans this is a non issue. I get wonderful sounding delay as I use Delay a lot.

After getting all my levels set correctly and outputs this thing sound great. For $499 which is now the lowered price of this unit It's a complete steal. It's very Organic sounding which surprises me like it has a built in preamp tube somewhere to warm it up. I had a Vox board years ago and it had a Preamp tube in it and sounded great but didn't provide me with the flexibility I wanted. It was from the Valvetronix series.