I don't think MT are trying to compete with 24 or 12 port Gigabit solutions from Cisco or Juniper.
But a 4 port Gigabit system with some extra 10/100 ports, running on low cost hardware, plus redundant PSUs (easy) would be an excellent solution for several applications including corporate and campus use.
I can think of a lot of customers who'd use that.
I am getting the feeling that single-CPU hardware is reaching the limits of technology, so chip makers are going multi-core - and board makers multi-CPU (quite right to note the different, thanks!).
FWIW, the new Xbox 360 games console has 3x 3.2GHz processors - now that could make a great router platform ....
... just need to add some Gigabit line cards ...