We love our Bibler Lighthouse. It weighs 3 lbs 3 oz but is big enough for 2 plus all our gear. We carried the smaller Firstlight on the AT in 2003, but it was too small for 2 plus gear and we experienced condensation problems. Remember though that the AT in 2003 was extremely wet.
One feature that we really like about both tents is that we can set them up from the inside (Think rainstorm). When we stop we unroll the tent, throw our backpacks inside, crawl in and put up the poles. The poles are inside the tent and the tent is freestanding. Since we normally hike without hiking poles we save the weight of the poles. Freestanding tents allow us to set up on rock or other durable flat surfaces. That sounds like a hard bed, but we actually preferred the flat, well-drained sites to muddy sites.
Ken