the big thing to realize with the crown lofts is that the L1s look over the ocean but L2s look over the sports courts (basketball, mini golf, etc) and i think the boardwalk area. Some people like L1s because they are quiet and private and have good ocean views. Some people like L2s because they can see all the action. There are occasional complaints that the L2s are noisy, though with the doors closed the soundproofing is generally pretty good. The L2s definitely have less privacy. So, one's not really better than the other, but you may prefer one over the other depending on whether you want ocean/privacy/quiet or action/fun views/something totally different. also, L1s are generally a little more expensive, but not much (maybe a couple hundred dollars).
If you choose an L1, the best views will be from the middle of the curve (the floor where the CLS are is slightly rounded). that is room 1710 on port, and whatever's right across from it on starboard (1748, i think). we were in 1708 on allure, and it was a great room. you can tell from the deck plans which rooms are in the center. 1702 has a sort of hallway when you walk in which some people like, but i think its balcony is slightly smaller (and same with 1756 on starboard). if it was up to me, i'd try for 1748, or the room right in front of or behind it. but really, they are all fantastic, and like no other room out there.
there is smoking allowed on the port side of the pool deck, so occasionally when we were in port and not moving, we could faintly smell smoke on our balcony in 1708. as a result, we booked on starboard for our upcoming harmony cruise. it would probably not bother most people, but DH is very sensitive to it.
as for balcony size, the balcony on the CLS is smaller than that of some of the other suites, like owners suites. the balcony holds two loungers and a table between them, and that's it. there is room for a little more furniture - i've heard some people request dining tables or more chairs - but not a ton of space. the double-high ceiling is great, though - it makes the balcony really feel airy. other suites like the owner's suite and grand suite have wider balconies (OS is generally about the width of 3 staterooms, GS about 2 rooms wide), so they often have loungers and also a dining table and maybe some other chairs. you don't get the high and airy feeling, though. the CLS being on 17 is also great now that the suite lounge and coastal kitchen are there. We've stayed in both GS and OS and they are fine, but you don't really get the "wow" you get with a CLS.
if you want a bigger balcony, you might want to look at the A4 aqua theater suites. they are one bedroom suites way at the back of the ship that have a wrap around balcony with views of the aqua theater. they are on decks 11, 12 and 14 (no deck 13 on oasis). i would not stay on 14 as the balcony is tiny, but on 11 and 12 the balconies are huge and have fabulous views. the bedroom is quite tight on 12, but for two it is ok for a week. if you'll have kids with you, i wouldn't do it. i haven't been in the suite on 11, but it's bigger than the one on 12. if you'll have family with you, the larger aqua theater suites on the lower floors have two bedrooms and way more balcony space, but they are $$$$ compared to the CLS, OS, GS, or smaller aqua suites.
sorry if that's too much info. we were just on allure last week so it's all fresh in my mind.