Is routerboard Suitable for isps?

Hi all I need help

I have 15 mbps L line having 150 users and want to make PPPoE server.

which routerboard is suitable for me for 24X7 uptime.

how many users i can make on Mikrotik pppoe server.
can i give static IP (public ips) to selected users.

Yes, you can give static and public ips for your clients using pppoe.

You can have as many ppoe clients as your license allow, check the wiki: http://wiki.mikrotik.com/wiki/Manual:License#License_Levels

AND, of course, as many PPS/mbps your hardware supports.