Here is why I would not run SME on a laptop:
a. NIC driver issues, do not forget that SME v6.x is based on RH 7.3 (major concern)
b. Laptop will need to be running 7/24 if SME is used a departemental or firewall server
c. Would require 2 NICS if used as a gateway.
d. Laptops are not built to run 7/24 for long periods of a time (by design they are made to be mobile, frequent shutdowns and restarts, not to be left running days at a time).
Everything depends on how critical or level of uptime you are looking at.
Hope it helps,
Luis