From the Sprint press release:

Starting today, new and upgrade eligible Sprint customers can get iPhone for just $22 per month with iPhone Forever. Anytime customers don’t have the latest iPhone, they are eligible to upgrade. They bring their iPhone, upgrade on the spot and away they go. It’s that simple. iPhone Forever is available on any eligible Sprint rate plan and upgrade eligibility is always included in your price. Qualified customers can get1 a 16GB iPhone 6 model at Sprint branded retail stores, Sprint.com, 1-800-Sprint-1, Best Buy and Target.

At its heart, this seems like a solid idea. Pay a fixed monthly fee, then trade in your phone for the latest and greatest.

Lots of unanswered questions in the fine print, though. Will I only be eligible for the lowest memory footprint (like the 16 Gb iPhone mentioned in the press release)? How long will I have to wait for my new iPhone? Is there any guarantee that I’ll get the new phone within a certain number of weeks after launch?

From the chart in the press release, it looks like a real cost savings over the other carriers, though the chart appears to only focus on one type of ownership, a single phone with an unlimited data plan. If you are part of a family plan, for example, those numbers will change.

There’s also the question of reliability and availability. Does Sprint’s network coverage match that of Verizon, for example?