Here are the current problems with the Triumph:
- Low end radio. You will get a weaker signal than almost any other phone on Sprint. If you're in a good signal area, who cares. If at home or work you have marginal signal, don't get this phone.
- Battery life is on the lower end for similar phones.
- Automatic brightness takes a second or two to adjust.
- Camera is garbage. You don't want to take any real pictures with this.
And other problem you may read about can be fixed through a ROM.
And Cricket is always open to allowing flashed phones that they don't sell on their network. Nationwide coverage. Where Cricket doesn't cover, Sprint coverage counts. I get 3G coverage on Sprint networks. I get the Android plan for $55/month.
The main problem with using Cricket as a bring your own phone CDMA carrier is that it's not truly nationwide - Cricket runs an AWS network in many of its cities. A flashed phone is only going to be dual band. So if you've got your flashed phone in a Cricket city that has AWS, it won't roam on Sprint's network because it's a Cricket area, and you can't connect to Cricket either because you don't have the right radio. I believe you can mess with the PRL to make it roam on Sprint anyway, but that's getting over my head.
If you could get it to work it would be great for phone costs - you can get an excellent condition Samsung Fascinate with a bad ESN on eBay for $75 shipped that is a much, much better phone than the Triumph.