I've used Luminance (well, it's the only HDR program i use, but I just don't HDR that often). Sometimes I use it in conjunction with Hugin Panorama Tools to stitch layers and then hdr-merge in Luminance. Takes a while and a lot of Swap space...
Like the review says, it's powerful. It's very powerful. There's almost nothing you can't do.
But the biggest problem (and i've read this on other reviews too, and in my own experience), there's no way to learn what anything does except without trying it (invest in more RAM if you want to experiment). There's an almost infinite way to create the HDRs (plus 6 'presets'), then another infinite way of 9 types of tonemapping algorithm. Some look good, some look cartoony, some have that horrible 'fake hdr' look, some are great.
If you've got a free weekend (or a free month), get it, try it, and experiment.
Also, my other beef is that it only tone-maps using 1 core of my 6-core Phenom. With a stitched HDR (like 300mb), some tone-maps can take an hour. That would be 10 minutes if it could use all 6 cores...
and examples (look at the filenames for what algorithm i've used).
They're not meant to be good, just representative of what each algorithm does:
