I've never had an issue with any of the replacement LED's I've used, either by converting the fixture using an LED tube or by replacing the whole fixture.
The LED itself will last a very long time, the issue is cheap boards and wiring used to make the rest of the fixture. There's a lot of cheap crap out there with LED's, if you buy actual quality stuff you should have a MUCH lower replacement rate than anything fluorescent or incandescent. Of course, if you buy cheap crap, not so much.
For Rob, if it's blinking it's likely toast.