Flax, the 2402 is probably the best bang for the buck out there. It's relatively light and has plenty of cool features, like switchable lo-cut filters and clip limiting. You can run both channels off 1 mono signal just by flipping a switch, or you can biamp. It's stable at 2 ohms per side (or 4 ohms bridged), which means you can run 2 4 ohm cabinets or 4 8 ohm cabinets per side.
The fact that it's discontinued means you buy a used one for much less money than new. You can get one delivered to you off ebay for right at 500.00.
Power = headroom. You would rather have too much than too little. The 2402 is definitely not too much power. A good rule of thumb is to have your power amp produce 1.5 times the watts your speaker is rated (anywhere between 1-2 times is ok, really). That way, nothing gets stressed too much. Underpowering the speakers will lead to clipping the amp, and clipping will lead to blown speakers. Really, there's no such thing as too much power. You can always turn it down. It ain't like tube amps where they sound sucky if they're not loud (at least that's what my guitar player says).
Looks like the Acme is rated at 350w, and available in either 4 or 8 ohms. That means you could get 2 4 ohm cabinets, run 1 on each side of the amp, and be giving them 700 watts each. You could do the same with 2 8 ohm cabinets and be giving them 425 watts each. Either way would work. Some folks feel that 8 ohm cabinets tend to be a little tighter sounding. See if you can compare them for yourself.
If you knew you would not need more than 2 cabinets, you could spend less money and get the PLX 1602 and 2 4 ohm Acme's. That way you would be giving each cabinet (running 1 per side) 500 watts. In a pinch you could run both cabinets off 1 side of the amp and still be giving each one 400 watts, and the other side you could use to run mains or monitors in an emergency. Of course, that holds true for the 2402 as well.
My personal reccomendation between the 2 would be the 2402. They weigh the same, and more power gives you more options if you want to expand your rig.
Other brands to look at would be Crest and Crown. They both have amps with similar specs, but I don't have any experience with their lightweight amps, so I can't comment. I will say this, though. While the D-fly was in shipping I asked Mica what it sounded like. Her response was,It sounded really good here, and gave a description, but it'll sound different through your amp... we use a hi-fi reference rig. I told her what my rig was, (it's in my profile) and she said, Oh, ok, that's definitely a hi-fi setup.
So it sounds like the QSC amps have the blessing of the mothership, at least.
Good luck,
Charles