My impressions of Ball Hop:
First of all there are play control issues. That's one of the most complex aspects to a game because it's not something one can quantify or even describe most of the time. You have some games that _feel_ right like a Legend of Zelda and some that do not like so many Zelda knockoffs.
If anybody here has ever played one of those action games that doesn't feel right, such as one that attempts to pass eight-directional movement for full range, then that's a lot how this Ball Hop plays. The trajectory and momentum of balls doesn't seem to correspond to flicks as well as Skee-ball, so that it's hard to find that sweet-spot by making smaller adjustments because they don't seem to be detected all that well.
The framerate is on the choppy side, in that it seems to have less FPS than Skee-ball. And perhaps most importantly is the limited field range. Skee-ball angles the lane in such a way that you have the complete screen width in which to launch balls, where Ball Hop has the side bumpers in the way and less overall space. Here's a side-by-side screenshot comparison to illustrate:
http://img202.imageshack.us/img202/6986/img0250b.png
More subjectively: I consider the banners and IAP incredibly tacky.
Coin Drop is $.99; does a great job of revamping Plinko for iOS in a very charming way; has _no_ banners and _no_ IAP; has produced free updated content; and is an all-around great+polished game. Why couldn't you have looked toward that as a model? "Because everybody else does it" is not a good enough excuse to throw in banners and IAP. At least it shouldn't be--but I suppose monkey-see-monkey-do is a mark of modern gaming.