I have the delta backyard buck, and agree it's good target for the price. As others have stated, it will last substantially longer if you keep it out of the weather, although mine has been out for 12 months and is still doing it's job.
Additionally, to offer a tip I have learned, if you take a fiberglass rod, of the variety driveway relectors come mounted on, and cut it with a hacksaw down to about 14", you can ram half of it into the detachable head/neck, and the other half into the body of the target, and it will keep the head from getting loose.