Looks like your not getting much help, I have no experience with the new
Shure SLX series, nor the G2. However I have worked with the
Sennheiser 100 Series Lavs several times. I'm currently using 10 of these for a summer musical. They're performance is pretty good for the price, probably the best bang for the buck wireless rigs out there. I've personally never delt with
Sennheiser, but I heard there support is rather cruddy. Although I've never used/heard the SLX series, I'd prefer the sennheisers over them simple because the SLX series use plastic enclosures for all the equpment. While, the 100s have all metal enclosures, and I really like the
sennheiser packs a lot. They have a nice plastic
cover for all the buttons, which is pretty helpful because most lav techs in HS don't understand the concept of "
power locking". The
sennheiser seem to be a nicer buy (I believe better performance too), the SLX just feels like
shure released it based on capturing more of the market by making a low end selectable frequency wireless
system. Just to
clear things up, I'm not necessarly a
sennheiser guy, I actually prefer
shure simple because it's more user friendly and just comes more logical to me. I really like the U and UC series, the ULX series isn't bad but they're plastic enclosures which generally aren't a good long term
purchase.
Shure are my favorite for the most part, sony I like a lot too, they're actually the hardest to figure out but I've been really impressed with the
system's performance at my main facility. But they're really pricey, but they have the most amazing range and clarity.
Anyway, I'm a little off topic. To sum it up, I vote for the G2s.