I own the Note 3 in white (since that color somehow has the highest resale value), but I used to have the onyx/grey one, and they're both beautiful beasts of technology. I didn't care about its looks or its back since it will have a cover anyway. It's rather slim and feels much more compact than the Note 2, which is a nice plus. I test all my games in its default browser and within Chrome. I will recommend that beast phone to anybody looking for a phablet - it's the best! If you don't mind straying a bit away from Android, then consider the Nokia Lumia 1520 - it's such a big, beautiful phone, but you have to handle it first. You could also wait for the Galaxy S5 and the Sony Xperia Z2 (they're both 5+ inchers and are also water/dust-proof!). Personally, I will always desire a phone with removable back piece and/or SD card slot.
If you are concerned about lower specs, then just get, additionally, a pre-paid phone or a Moto G (amazing little mid-ranger!). Again, if you don't mind moving away from Android, then pick up a Nokia Lumia 520/525 for pure dev purposes, unless you fall in love with it!
Good luck! Make sure to handle them all first so falling in love with one becomes easier!
EDIT: Make sure to check out the Nexus 5, too! Cheap high-end phone ftw.