I'm not 100% sure but I think that firmware updates a year or two back have fixed the battery draining thing (if it was actually an issue as I often forgot to remove it and never had a problem).
The system as a whole is certainly not up to the quality of the dedicated data systems like AIM, 2D, etc. The software is particularly unintuitive and does not seem to split out your laps for you in an easy fashion so it's very difficult to use it to compare different runs. One of the guys who worked on the software is on the forum and is very friendly and helpful. I just think it needs more time put into development to make it a more useable system that can compare to the low end AIM / 2D / Motec etc. At the moment it seems more of a sales pitch item than a genuinely useful bit of kit for people interested in analysing data.