Okay yeah, let me try to go into a little more detail. I'll try to explain this as best as I can but sometimes it's hard to pinpoint exactly why (like, sometimes it just feels better and I can't put that into words i dunno).
Having the windows pop out when editing levels is much more appealing to me. It gives me more room to look around the map (I'd have to constantly compress and expand the level list in BL to do the same in it), plus I feel more comfortable with opening and closing a level window than having to manage my tabs. The tabs do have the advantage of allowing me to quickly switch back and forth between levels which is nice if I'm trying to remember something, but otherwise I do just prefer the additional window.
CE also has the slight advantage of looking more minimalistic. Really it's a small difference between the two, but I prefer the drab, uninspired look that CE has. I probably sound crazy or something, but ironically enough the dull appearance is something I advocate.
I may have missed a small thing or two, but those are the major reasons. If BL has those features but I don't know they exist, then you have every right to call be an idiot (and then promptly tell me where to find them :>). And really it's not like BL's interface is majorly flawed or anything like that, but hey that's personal preference.