LifeSpan has a good price range of models and their customer service is said to be comparable to the high-end brands. You could also look into Landice and True. The only experience I've had with Precor is at hotel fitness centers. During bad weather, I run on a True.
It's best to try out different models in person so you can test them for flex, cushioning, appropriateness for your height/weight, etc. Feel is very important.
If you don't have local dealers where you can test in person, maybe look at local gyms or the YMCA to decide what features you want in a treadmill in order to narrow down your shopping choices.
Congrats on this next step!
26.2 | 13.1
+ Quantum Conundrum
+ LittleBigPlanet 2
Far Cry 3