PCC works well, see the Wiki. For Hotspots to work right you'll have to add rules to capture not just forwarded traffic, but also new traffic originated from the router since Hotspots always transparently proxy DNS (and possibly HTTP?).
1- Is the blance with Microtik is better than dual WAN router like this
http://cgi.ebay.com/Linksys-RV082-8-por ... 48382c783c
Then connect this router's LAN to Mikrotik.
2- if it is not better, It would be helpful to put the latest code that work with RouterOS v4.2 for Hotspot user accounts:
Two WAN and one LAN. The LAN will have about 80 Hotspot users
3- will MIlrotik RB450 be enough for this
Note:
-One of the DSL line are coming from farther distance(a house near by)