The interface might be a bit complicated for some users, it certainly doesn't look like most cd/dvd-s burners, but once you get used to it, it is fine. Advanced user will appreciate the numerous settings covering all aspects of the burn process. Anyway for such a small application (even portable) it does all I need it to do and it does it well.
I don't think InfraRecorder works with HD-DVDs and Blu-Rays. From the list of free alternatives to (the bloated) Nero, I've also used CDBurnerXP. It was ok, maybe not as reliable as ImgBurn (as far as I can remember it lacked the option to check the disk after the burn process - please correct me if I am wrong). Anyway, reliability of such a program is hard to test.