I've used both for about 5 years. Terminal Server works really well if you
only need a few Terminal Servers. Citrix adds a lot of features that really
come in handy as your user base grows. Citrix is an add-on for Terminal
Server, so you still have to own TS and its licenses before you install
Citrix. For 45 users, if you can put them all on one Terminal Server (very
likely), you will probably NOT require Citrix, although your exact
requirements will determine this.
Each session RDP (Terminal Server) or ICA (Citrix) requires a bare minimum
of 26.4 Kbps to function at about 800x600 @ 16 bit color. As you add
features like remote printing, sound, drive mapping (to the remote computer),
increased resolution or color depth, graphically intensive apps... the
bandwidth requirement will grow. I find that budgeting for 36Kbps-128Kbps
per concurrent connection is more reasonable and safer than what the
manufacturers say you need.
Since the data that users see on their remote computers are images that are
pushed from the TS/Citrix server, your upload bandwidth MUST be sufficient.
With this in mind a $30 /month ADSL connection will not be sufficient for
more than 5-10 concurrent sessions at best. If you use a SDSL (768Kb or
1.54Mb) or T1 (1.54Mb) connection you can increase this number to the 20-40
concurrent session range.
Terminal Server Planning Info here:
http://www.workthin.com/tsao.htm
Server sizing:
http://www.workthin.com/tshw.htm
Citrix info:
http://www.workthin.com/citrix.htm
Other add-on programs (some Citrix Alternatives):
http://www.workthin.com/tsao.htm
Patrick Rouse
Microsoft MVP - Terminal Server
http://www.workthin.com