Some work and don't feel like an afterthought, it's a large area and they must command a presence (e.g. like Dredd) and others are just awful (e.g. Wonka)
BM66 looks awesome IMO, I had a FT and loved the topper it became part of the soundtrack.
I couldn't see me parting with much more than £300 for a topper, anything more and I'd put it into a new pin fund.
Have seen a couple of homemade ones (Indy and Black Rose) that look cool would like to see more of them from the creative types amongst us.