Pete: Thanks for this write up, it pushed me to purchase the 1400 t-top for my Tacoma. I LOVE THIS TENT!
The Dude: SPEND THE EXTRA CASH FOR THE EZI-AWN T-TOP!! (or find a used one) I had the same dilemma and I'm happy every time I camp that I bought it. Having the versatility to put up the walls and have a wall tent is priceless! The quality is unmatched.
Note: My tent had the velcro at both doors to seal the tent, the hinge seals up nicely also, I think these are recent improvements that you may not find on an older used model but it is easily fixed.
The screen, This is VERY high quality durable material. (Imagine a mesh that could slow a bear or lion down) A finer mesh would stop no see-ums, but it wouldn't hold up for life like this type of screen does. - The answer? spray a bug repellent on the screen. The little bugs can't just fly through the screen, they have to land first and then crawl through, a repellent keeps them from doing so.
Will at Sierra expeditions is great, I bought mine slightly used from Paul At Equipt1 who is also top notch.