Rating: 4 / 5
I find the Whisperlite to be MSR's easiest liquid stove to use, and certainly the nicest to lug, bulk and weight-wise.
Simmering performance is best with a light touch on the fuel pump--try using less pressure if you're having difficulty achieving a simmer (although it necessitates frequent pumping during use).
MSR doesn't seem interested in a making lighter version, and perhaps there's insufficient market for it. Certainly, some Ti bits could shave a couple ounces w/o affecting performance or ruggedness.
I'll also note that by MSR's own performance specs, the Simmerlite is one of their least efficient LF stoves.
If my arithmetic is correct, the Snow Peak WG stove is virtually the same weight as the Simmerlite, once you subtract the fuel bottle's weight from the published kit weight. So there's an option for those who want something different. I've not used one, myself.