I use the the Rocktron V300, which I've used for the past couple years in my SMS/E120 Jerry-esque rig.
Pros
-Reliable & hum-free
-Plenty Loud
-Tone-shaping options
-Bridged/mono modes
-Fits in single slot rackmount case
-Cools efficiently, internal fan works well
Cons
-While it doesn't detract from the overall sound of the rig, it also doesn't add any character or pleasing aural effects (to my ear).
That one drawback has been enough to make me decide to replace it at some point with either a Mac or a tube power amp (been looking at Mesa's 6L6 amp, I love the way Mesas sound clean). By contrast, when I still had my Euphonic Audio iAmp Pro (boutique D-class bass amp), I tried slaving its power section, and let me tell you: huge difference. It suddenly had sparkle and clarity in the highs (without being piercing) and depth in the lows. All of a sudden, the whole rig was way more transparent and alive -- it was like my ears just went "ahhhh." Nevertheless, YMMV; the Rocktron is a top-reviewed piece of equipment and many people like the way it sounds a lot, and it has a bunch of features that are all pretty darn reliable and high-quality.
If it were me, I'd go with a higher-end power amp right off the bat (SS or tube) instead of ending up wanting to replace components later on. And, maybe most importantly of all, I'd go to some lengths to hear it and play through it if possible before buying. Good luck.