I use an hmc40 and it has worked pretty well. The 40 is actually a bit sharper than the 170, but they have very similar mojo if you take a little time to match the scene files. The avchd codec breaks down more quickly, but for average work, it cuts just fine. The 40 is much less sensitive, so not a good match for darker scenes. The 40 is a real bargain for IQ, but it does have a few quirks like poor VF, not enough ND. Unlike the AC90, it does have a WFM.
