i'm personally a user of the black magic tire shine gel and i love it. i apply it using a foam block i purchased off of detailersdomain, and i find it works great. so far the one bottle i've bought has lasted me over 20 applications and maybe 1/3 still left. the foam app block makes it much easier to apply, spread, and wipe around ensuring a nice even application that doesn't "sling" off when the car is driven. my favorite two things are the fact it doesn't sling even if driven directly after use (which of course has to do with how i apply it), and it lasts weeks on end.
to hard core tire shine users let me give you a heads up, when used often (was washing and then dressing my 2004 S2000 two to three times a week) this product can start to built up quite a bit. if you find this happening to you, simply use your favorite tire cleaner/APC and agitate with a stiff brush. This helps to even out the build up, and ends up giving a really awesome matte finish that lasts for weeks.
if you don't like this product, or have had bad results, be careful how you applied it as it makes all the difference. find the tire shine that bests fits your needs (how it's applied, the matte vs shiney look, durability, cost, etc) and stick with it.