Indifferent, mostly. Red Sox have done very well in Interleague Play over the past few years, so I guess it's nice to have a "soft" part of the schedule, though
Honestly, it's nice to see a few different teams every year. Gets you those couple teams that you wouldn't see unless you matched up in the World Series. Saw the Mets last year, the Giants, Brewers this year, going to see the Cardinals on Saturday, etc. Adds some fun to it, get to see new ballparks, etc.
The "Rivalries" are mostly stupid, however. Makes sense for places like NYC or Chicago, Texas, LA, etc. though. Some of them are really a stretch, though, and MLB just had to go WAY back to find one, or just match up whoever was left. Boston/Atlanta is one that no one really gets excited about, but we get a bunch of games against. Not because there IS a rivalry, or because they pay any attention to each other, but because a billion years ago (they left in 1953, to be fair, but hadn't been relevent for several years before that) they played in Boston.
Creates some real imbalance in the schedules of competing teams when you factor this in, too. For example, the Cubs play the White Sox, who have been good lately, while their competition, the Cardinals, has a "rivarly" with the Royals, who they usually feast on. In regular play, at least every team in the division gets to tool on the same crappy team (like the Yanks and Sox used to do with the Devil Rays), so it at least evens out. Adding in Rivalry games mean that the person you are competing with doesn't have to face the same opponents, though, which throws things out of whack a bit.
Also just not a fan of the problems with rule changes between AL and NL ballparks. I think it's a real disadvantage to the AL teams when playing in NL parks. You lose one of your big bats, or are forced to put him in the field, where he rarely if ever plays, so you either bench him or sacrifice offense (and lose your normal 1B or outfielder). You also have REAL automatic outs with the AL pitchers. NL pitchers are used to batting, or at least laying down a sac bunt, etc. AL pitchers just walk up there to take 3 strikes and sit down again, mostly. Usually at the coach's request, because they can't risk getting hurt. Seeing a pitcher get hurt swinging a bat or running the bases is a huge waste. A little of this is personal preference, too, as it's just not exciting watching a pitcher bat, as they suck (in most cases).
It IS fun to see double switches, more pinch hitting and running, though. When you don't do it as much, it's interesting to see. Little more strategy involved. Again, another advantage for the NL club, though, as they're used to doing these things, and at a fundamental level, their roster is built to handle it. Again, with the Red Sox as the example, You're forced to bench Ortiz, Youkilis, or Lowell every game you play in, which sucks, especially to watch Wakefield "bat".
Gotta be great for the NL club, though, as not only do you not have to put your pitcher up to the plate, but you get to play a whole other player, or rest a guy. Of course, their roster may not have one more guy with a good average, as they wouldn't get regular play, but it's still an improvement over the pitcher. Their starter can stay in longer because they don't have to pull them because they're up in the lineup, and you don't have to pull another position player for a double switch.
While I like seeing the different teams and ballparks, I think that overall, Interleague play is a little too "cute" and forces teams into awkward positions just to make some advertising money. It's not so bad that it should go away, it just kinda sucks a bit from a competitive standpoint, especially when the matchups aren't consistent across a division, so the guy half a game behind you gets to feast on a weak team while you get pounded by the leader of another division...
(I am an Angels fan, so I can mock them!)
