Here are your likely pitching matchups for the NLCS. Long story short: the Giants rotation is, in fact, really good, although the Phillies will still have noticeable xFIP and SIERA advantages in four of the seven games.
If you really want to nitpick the other side, it does appear that two of their starters benefited quite a bit from luck-based stats this year - Jonathan Sanchez with a low BABIP and Matt Cain with a low HR/FB rate. For Cain, at least, that's nothing new, as he seems to post unusually low HR/FB rates every single year. We've had discussions in the past as to whether he might actually have a rare skill at depressing those rates, or whether he's just had a very long stretch of good luck. I don't know which is the better explanation. (For whatever it's worth, his career home/road splits for HR/FB seem fairly modest.)
On the other hand, one other thing to keep in mind here is that the stats in the table below are cumulative stats for the entire 2010 season. Using full-year stats is generally a good idea because it provides objective, across-the-board time parameters that you can't manipulate. But at the same time, in reality, if you're trying to evaluate present quality, stats accumulated in April 2010 are somewhat less relevant than those accumulated in September 2010 and not so much more relevant than those accumulated in September 2009. So just looking at full-year 2010 stats is, in some sense, arbitrary, and doesn't necessarily tell the whole story.
For the Giants, September 2010 was an especially good month for all of their top four starters (xFIPs for the month: Lincecum 2.21, Bumgarner 3.08, Sanchez 3.56, Cain 3.57). Of course, that's a small sample so you have to take that with a grain of salt. But there is at least an argument that can be made that at this instantaneous moment of 12:30 p.m. on October 15, 2010, all four of the Giants' probable starters are better than or equal to each of their probable opponents from the Philies, only one of whom (Blanton) greatly outperformed his full-season xFIP in September.