i cant offer reviews, i can only give general ideas.
Theres three broad classes of bikes, road/racing bikes, mountain bikes and hybrids. For road use road/racing bikes are the best. They are very light, have thin tyres, and are generally no frills (no suspension for example). While they'll zip on the road, they'll do poorly off it. The posture is also often like you may have seen in racing, you'll be forced to lean forward.
Mountain bikes are heavier, have thicker and wider tyres often with gripping treads (which means more friction and grip, which means really slow but stable riding). Usually quite cheap though since they're not for everyday use (because they're so slow)
Hybrids cover everything in between. Often have thinner tyres with smoother treads, but may have mountain bikey things like suspension.
I personally prefer hybrids, because racing bikes are usually pretty expensive, and easy to break. but if speed is your thing go for a road bike!
I didnt know mountain bikes were slower. Hybrid sounds like the best of both worlds. I personally dont like the road bikes. Im not in for the speed so that takes care of the road /racer bikes too.