The PC tuneup feature is only in the paid version - but the icon for it is still shown in the free version. Yes, the inital update is very slow, but if actually complete succesfully, future updates will be much smaller so the speed isn't much of an issue for them.
I see. after using it for a day I see its very light and no annoyances really other than that PC tuneup icon which my clients can live with (I can't personally stand any unnecessary features icon) but now I finally find another decent free AV to recommend to my clients
5.2x is pretty light, and gets lighter the longer you run it, and the longer it has to store file hashes. Install it, then run a full scan, then let it run for a couple of days, and see how it feels. Unless you have an old, underpowered computer there shouldn't be any noticeable impact after a few days. We install Forticlient on approximately 100 machines a week to tie it into VPN's through Fortigate, and the only complaint about weight I have fielded was someone on a slow, improperly configured dual core running WindowsXP. I have had no issues getting the official version for the guy saying the installers don't work; http://www.forticlient.com