I've been doing a lot of reading on the acoustic amp stuff and so far the one every publication universally raves about is the Genz Benz Shenandoah 200. It's pretty big though, and it weighs like 70lbs, has two channels each with 1/4" and XLR inputs that are always active, meaning you could theoretically plug four inputs to the amp. Its a 2x10 combo with 2 tweaters that can be adjusted independently. All the reviews comment on the headroom this thing has. Supposedly loud enough for an acoustic guitar to outblast many tube half stacks and drums without farting out...that's a tall order.
Price wise they aren't too bad ....street prices are around $1000 new and they are starting to show up more often on eBay now that they've been out a while.
I guess the main drawbacks would be the size and the fact that the Alesis DSPs (two of them) don't offer changable parameters other than effects level, but I believe it has an effects loop for each channel so you can insert your own.