The
RX-V2500 does have THX. The software side of THX (the THX processing mode) isn't all that relevent these days - Dolby EX provides capabilities comparable to THX EX, for example - and the certification process is often not done by companies like Outlaw or Rotel because of the licensing and testing fees required, even when products are more than capable of meeting THX's requirements. Bottom line: while some people are fond of THX, many people (myself included) don't think it's an important feature.
Three years or so ago, a bunch of us were asking questions similar to yours while waiting for the Model 950 to start shipping, and I compiled a
chart comparing features of various pre/pros and receivers. I've revised it a few times since then, and it's currently a fairly decent overview of pre/pros currently on the market (I moved the receivers to a
separate chart a while back). This can give you some idea of what alternatives exist and what they might offer that differs from the Model 990. Based on everything we've seen so far on the Model 990 (and with the newsletter from the other night, we have a lot to work with), I'd be hard pressed to find a pre/pro in the price range with a better array of features. Features alone aren't the whole picture, however: the unit needs to sound good, too. A couple of the pre/pros on the chart are not available yet to know how they sound (along with the 990, Emotiva's LMC-1 is still in development, although it may begin beta testing soon based on what I've read on AV123's forum). Assuming that the 990 sounds as good as the Sherwood it is related to, it will represent a very compelling - and potent - value in the pre/pro market.