No frenzy, just a lot of opinions.
First off, don't worry about your warranty, a tune in all likelihood won't cause any issues there.
As far as the "best", here's a secret; most tuners Stage1;2;2+ files are all pretty even. I think there's a YouTube video of a race between APR S2 and a Revo S2 and it's a dead heat. Choose a tune based on 1) how close you are to a dealer, 2) if they offer any features over a different tuner (i.e. APR program switching with CC stalk, Uni has the Connect switcher and GIAC Flashloader, DM has the programmer, etc) and what your overall goals are for the car, such as if you plan on BT in the future don't choose a company that doesn't offer a BT file or you'll end up switching companies anyways.
For me, I needed the abilitly to switch tunes in my garage due to emissions, so I went with DM because of their programmer option. However they no longer offer the programmer so that doesnt help you. Also think about customer service and support after the sale- firsthand I can tell you DriverMotorsport will offer basically zero support after the sale. I can't speak firsthand about any other offerings.