The problem is that sometimes it is hard to get service without the subsidy penalty.
Fortunately, it is much easier now than it was a year or so ago, thanks to Straight Talk and Net10's SIM-only plans (both give you choices of AT&T or T-Mobile's network, although new AT&T ST SIMs may be temporarily unavailable.) and T-Mobile's new plan structures.
When my contract is up, it's off to ST (if they are offering AT&T SIMs again at that point) or Net10 for me.
Net 10 is Straight Talk. They're the same company. If you call Net10's support line it declares itself to be Straight Talk. The differences are that ST is sold only by Walmart, Net10 is sold by other stores and Net10 can be $5 per month more expensive unless you use their "Auto Refill" service.