How come User Manager is no longer available to download for the RB500 series, but is available for the RB200?
I was just about to purchase a 532A for this - should I not bother? 
User Manager just chews through resources - as the sessions grow, memory decreases. Memory is finite on any platform, so a routerboard with more RAM is just going to run out of memory eventually unless the oldest sessions can be purged automatically.
That’s exactly why you should use X86 (a PC) for it. But if you really want, use this: http://www.mikrotik.com/download/user-manager-2.9.42-ns.npk
That’s not what it says on the wiki! If nothing is done to improve the way User Manager handles resources even a PC will run out of memory eventually!
actually it’s more a question of storage space
Storage space that fills up with log entries that I can’t see a way of deleting.
How can I delete these logs? I tried a script from another post but it did nothing.
Currently this feature is in production along with others. Please make other suggestions so we can implement them
logs can be turned off:
http://wiki.mikrotik.com/wiki/User_Manager/QA/How_to_turn_off_logging_for_specific_Routers
In the customer page, go to LOGS and delete