There are many viable options.
A leveling kit is a "budget boost"--ie, pucks over your existing coils.
The term "leveling kit" is usually used when the rear pucks are only an inch, making the front pucks only 2". After that, the term "budget boost" usually applies. And budget boosts (as well as coil kits) do generally level the jeep, meaning the front pucks are taller than the rears.
You generally want to stay 2.5" and below if you're keeping stock tires. And you are generally only a good candidate for a budget boost if you're confident you want be adding heavy aftermarket bumpers etc. that are likely to sag the stock coils.
That said, if you can afford it, a full coil kit by a reputable company with some good shocks will always be better.
I have a 2.5" TeraFlex coil kit with Old Man Emu shocks and 33x12.5R15 tires. It's a great daily driver.
Check out the stickies at the top of the JK section for some very good lift related threads.