I'm the same way when it comes to buying things, but I jumped on these. They're the best headphones I've had, but I have some issues with them. I figure I can give you a pretty balanced opinion on them, but I don't have anything equivalent to compare them to.
First off, the sound. LOTS of bass, but very clear. I kind of see what others are talking about with the mid bass hump, on some tracks the bass overpowers the vocals slightly. It goes very deep, and you can feel the impact, on the right track. Highs are very clean and clear, but not as transparent as my PL-50 on most tracks.
FLAC makes it shine though, all my mp3s around 200k sound flat in comparison, like the soundstage is squished. Mids are a little quieter than I'd like, but easy to eq, and sound really good. My first wow moment with them was hearing cymbals, and bass guitar, because there was so much detail that was new to me.
Some pure cons though, mostly with regards to fit, and source selection. These hiss, on everything I've tried them with, although I have no high quality sources. They hiss from my laptop, a few different PCs, my phone, and surprisingly, my Clip+. My PL-50 hissed on everything but the clip+, but was also much louder at a given volume. The hiss on the HJE900s is smoother almost, less intrusive.
I can't make them fit right. They fall out of my ears while sitting still, with any of the included tips. If I wear them over my ears, they fall out sideways and dangle. I know I'm getting a good seal, because of the giant bass, but there is NO isolation, and all the ambient noise sounds tinny and sibilant.
I'm reserving judgement until I try replacement tips, and possibly the sleek audio cable, but if I can't get them to work right, I'm going to have to sell them off. They do have amazing build quality, I have no fear of them breaking or scratching.
To summarize I guess, I don't regret buying them, and they sound amazing, if you give them some time to get familiar and maybe play with the EQ. I hope this helps you.