I compared the readings of my Sunpro gauge to an Auto Meter one, and they both read more or less the same. Good enough for me.
I figure there are good places and bad places to spend money, and a boost gauge is a bad place to spend a lot of money. It's just there so you can spot major problems quickly; if your tune relies on the accuracy of your eyes watching an analog boost gauge, you're doing it terribly, terribly wrong.
The only "premium" features that might be interesting are peak recall and warning, but those aren't necessary if you've got a proper tune, as a good tune will cut fuel if boost ever hits dangerous levels.