How much do you want to spend? Will you use this tent often on Backpacking trips?
If you want a good tent buy a Name brand tent like Big Agnes, Mountain Hardware, North Face, Eureka. MSR and the list goes on.
Check out Campmor.com, MountainGear.com, Backcountry.com, REI.
Go down to the local outfitter store and talk to them. Weight has a factor in it as well.
Rain proof..... I own 4 different single wall tents and all will shed condensation inside. Every double wall tent I own has never had a problem with inside condensation.
I use Mountain Hardwear skyledge series tents as well as Hilleberg and North Face. Sierra Designs has some excellent tents too.
Go over the Backpacker.com web site magazine and surf for GEAR and tents...they have good information there.
I use the wisdom that if a seam rips in the wilderness, that could spell disaster so I buy only quality tents with quality stitching and fabrics.
I trust my tents to weather anything below a hurricane.