It was...okay. The main character spends a lot of time in human form for budgetary reasons. But, it does feel like it's trying to make the horror work. And there's a certain side-character who shows up who's kind of a interesting choice. It's...a little slow, though. And they spend a lot of time on drama surround side-characters and villains, and building up things that...never really happen THIS season. It might have gotten better if we ever got a second season, but...I doubt it at this point.
I wouldn't mind it if the character got drafted into Legends of Tomorrow, though. Hey, it worked out okay for Constantine *shrug*
And I'd definitely recommend the comics for Swamp Thing. Swamp Thing's actually has a pretty solid track record for most of his ongoing books. The original Len Wein stuff actually has some pretty nice Tales from the Crypt style artwork. Alan Moore's run is, of course, the classic must-read. I hear good things about the Vertigo runs that came after, too, but I need to check those out myself one of these days.
Scott Snyder's run, where he crosses over with Animal Man was solid enough. And, I'd actually say that Charles Soule's run on the character is possibly my favorite run on the character since the Vertigo days. It's a slow start, but he actually ends up fleshing out some of the other Parliaments and the ending is kind of impressive, to me.
it's got none of the camp of the old show, but that's okay... I just add my own "do not bring your evil here"s to every time they switch to a shot of a foggy swamp XD it's like a drinking game but instead of dying of alcohol poisoning you just say the catchphrase of an old show a whole lot. XD