We really enjoyed Paradise Cove. We enjoyed all the activities, thought the show was excellent, and I thought the Mai tais were great. The food was just okay, but that seems kinda standard, unfortunately.
Honestly I mostly booked there outvof spite, because the Starlit Hui was still running when we booked Aulani, and that was just strike three on Disney taking away things I'd already planned on in about a year and a half stretch. I also didn't like the vague wording about what the Aulani luau would include (lots of "mays")--but now it may be more set in stone--and I knew what things there would be to do at PC. The canoe ride was big for us, and I was especially grateful for it (short as it is) since both our other canoe outings got cancelled.
As far as "getting away" from the resort, it's like a 5 minute walk and the cove looks pretty much like Aulani's Cove (and you can walk down there during the day if you want), so I wouldn't think of that as much of a difference. That said, the PC activities are at or near the beach and include some sunset photos (all printed on glossy paper--yuk) with the fire twirler, so that's a little different. You can also get some lovely photos there with your own camera; they have a nice view along the coast.
From what I hear, the Aulani show is more of a Disney style story, which is always awesome. PC is more like the Poly luau, where there are performances representing the different island cultures. They also have a really good house band playing Hawaiian music in between. I've heard it called cheesy, but IMO the performers were top notch. It's quite a long show, too--those same performers work non-stop for the whole time. It's amazing.
Good luck choosing. Whatever you pick, just forget the other choice existed and lose yourself in the evening. Some people call it one and done, but I'd like to do some kind of luau every time I go. Next time we will probably look for something small,just for a change, but we really enjoyed it.