A new Shure: the SRH1540

[G8YU]

I was just about to buy the SRH1840 and now they have a closed back model at the same price (for now). Now I don't know whether to wait on reviews to help me decide if I want the closed back SRH1540, or just buy it and hope I like it. Info on the 1540 is at Shure Americas | SRH1540 Premium Closed-Back Headphones
I've been looking at the higher priced headphone models and after eliminating the hd800, various Denons, LCDs, and Grados I was left with the ATH-W5000 or the SRH1840. While the W5000 is supposed to be great in most of the musical qualities I look for I was afraid the bass would be to thin for me. I read that the SRH1840 was also a bit thin on bass but was very "musical" with great imaging. I would guess the closed back of the SRH1540 would help with the bass, but I'm afraid it won't have the spacious sound-stage and imaging that I crave.
I'll report back with my experiences with the SRH1540 if I do buy it; and any of your experiences with Shure headphones are quite welcome too (might help my purchasing decisions).