SH2 in full router mode gives me a messy looking tbb graph with mean latency slightly higher than in modem-only. It bubbles around 20ms rather than 13ms in modem-only.
Pingtest pretty well confirms that.
Jitter can sometimes be as high as 2, but that was the case in modem-only too. The messy tbb graph doesn't seem to be associated with high jitter or particularly high latency.
Speed tests at tbb and speedtestnet are unaffected by SH2.
Wireless range seems at least as good as my WNDR3700 version 1. However, connections to my VM Freedom netbook and my Xperia U Android have been dropped in favour of other signals more than in modem -only. The up side to wireless is that speed tests on my wireless devices have been better in full router mode. Today I achieved a full 25Mb on my Xperia U in the same room as SH2. Previously in modem-only I maxed at 19Mb. I have 5MHz disbled because my devices aren't enabled for that.
My wife thinks the SH2 is good because you can tone down the LEDs. She has always wanted a car with a blue tint in the headlights.