I've used many iDEN radios, and currently have the i450 with Boost. It's not as rugged as the i530, and would like to upgrade to the i580. Wish the i455 was being offered when I signed up (only because of the black color). Boost is ok, but their customer service is the worst. The i670 would be a good choice too, not to mention the i880 but are asking too much for it without a contract.