Pentium M use less power, and are a bit slower than a Pentium 4
I thought all things equal (1.7 vs 1.7) the M was faster than the P4. but I am not sure.
The M is interesting how it works though to consume less power. It basically changes clock speed as needed. A 1.7GHz P4 will always run at 1.7GHz. An M on the other hand, will underclock its self as low as like 200MHz when there is little CPU power needed.
I have a Compaq nc6000 that I use for work. It has been solid for about a year now. From what I have seen in general at my office they are pretty good overall. That sounds like a pretty decent laptop you have. Definately worth getting those ports fixed.