I was only once in Omni Tower, but did not like it there. The studio I got was run down and was in an urgent need of refurbishing. This was in August 2008. Since then I prefer to stay in Dawin - twice so expensive, but much much better.The Omni Tower on Soi 4 (Soi Nanatai) has a special for their executive studio right now if you reserve 30 days in advance for 1119 baht per night. Seems like a good deal to me. I've stayed there before but it has been several years ago and it seemed pretty nice and LB friendly. I took 2 LB's back one night and there was no joiner fee.
Moreover, even if you get a decent room in Omni Tower, you need to take your LB through a flock of Arabic guys hanging out in front of the entrance and clearly expressing their disapproval.