Is anyone here using it on non boosted 4.3's ?
is it worth the $500 without having boost?
any input would be sweet.

If you know what you are doing, a lot can be gained by doing your own custom tuning. If you do not know what you are doing, you can mess up a lot of things!

If all you are looking for is a nice custom tune, then I would go with any one of the tuning options (Wait4me, PCMforLESS, or a local tuner shop with experience). If you want to fiddle around and have a moderate to advanced knowledge of what it takes to improve upon the factory tune, then it is up to you on whether you thing it is worth it to spend $500 on the HPTuners software.

I spent over $500 on my scan tool. I'll probably be picking up HPTuners at somepoint, but I will have a tune done before hand so I can see what was done.