Due to some negative reviews the first thing to address is the cable housings. The shifters come with two housings that are around 26" long one that is around 12" and are plastic lined. If you have a bicycle that only has cable housing running from the shifters to the down tube (just behind the steering head) and a short length of cable running from the rear chainstay to the rear derailleur you should be fine (I actually had to cut a few inches off of the shifter housings to match my stock ones). If you have cable housing on any other part of your frame you will need more housing unless you are reusing your old ones.
I had recently installed a set of Microshift on a 2003 GT Palomar with stock Shimano Acera rear derailleur and new Altus front derailleur. As I played with a Revoshift on a bicycle I had restored and sold I was curious to see how Revoshift and Microshift compared.
Out of the box the Revoshift feels more refined than the Microshift with their construction feel and shift indicator windows. Also in addition to the cable housings the Revoshift also comes with two cable crimps. Microshift has a lower price point but no housings or cable crimps.
Installation was the same as with the Microshift. Remove the hand grip slide the grip shift on and snug the hex head bolt to keep it from moving. Route your cables attach to your derailleurs adjust and tighten everything up. The only difference was I used the shims from my original grip shifters (that go between the shifter and hand grip) with the Microshift. The Revoshift design clearly has enough clearance built in so I did not use the shims.
As to performance... Both shifters do a great job. Both will take the 3 speed chain ring from 1-3 and back smoothly as well as rear freewheel from 1-7 or back individually or the whole gear range with one twist. The only difference is that the Revoshift feels more refined than the Microshift. The Microshift has a "snappy and locked in" feel when shifted while the Revoshift has smoother clicks between gears. For some reason it also feels like the Revoshift needs more wrist rotation to do a full 7 speed gear shift.
The two things that make the Revoshift seem more refined than the Microshift are also the two things that make me think these shifters are better suited to bicycles that won't see anything more than recreational or light trail riding. The smoother shifting caused me to accidentally upshift a gear by changing hand position shortly after I installed them (something I did not encounter with the Microshift). While smooth shifting on the road or recreational trail riding is great accidentally shifting a gear while moving my hand while doing more technical trail riding is not what I would want. Also I'd be more concerned with bashing a Revoshift on a trail than a Microshift. I think the Microshift would take more abuse and I wouldn't feel as bad having to buy another set if it didn't.
Bottom line... if you have a Shimano drivetrain I don't think you will go wrong with either shifter. I reviewed and gave both 5 stars because I feel that they are a solid purchase if used in the correct application.
In my case I'm not in a hurry to put the Microshifts back on as I'm not in good enough shape for any serious off road riding. The Revoshift is perfect for the recreational road and trail riding that I'll be doing in the immediate future.
One note... If you do your own maintenance and do not have a bike stand make sure you protect the handlebars before turning your bicycle upside down otherwise you will scratch or damage any type of grip shifter you have.
Lastly if you've never replaced shifters search derailleur adjustment and watch the Park Tool video's. Clean and lubricate your derailleurs before installing the new shifters. Use a little rubbing alcohol under the hand grips to remove them/install them.;