I use a jigsaw with a downward cutting blade ("worktop" blade I think some people call them) - never quite get a perfectly straight line with a jigsaw, but with these blades you at least have the neat edge visible while you're cutting. Could clamp a length of wood on to act as a guide - that'd help but I'm not that fussy/too lazy.
I'd have thought a table saw would be ideal with the appropriate blade, but i wouldn't fancy trying to cut an 8' length of conti on one on my own :hmm:
I get Homebase to cut the main bits, then i just have to cut the pinths down and trim a few bits.
You could use the mitre saw for trimming the plinths off, but you won't beat a table saw for clean cuts.
Jigsaws are the most convenient to use but give rough cuts which you will have to plane down to get a smooth edge. If you get a fine blade which cuts down as said and cut with the visible side up you should be okay, but will need a guide to get a good straight cut.
I'd just get it pre-cut. Much easier and no chance of a costly mistake either.
as a failsafe they also do a edge trim that is slighty wider say 17-18mm to the conti being 15mm which is great because it hides the rough edges and lets face it,it aint perfect when they cut it although atleast it is straight,
only thing is when i got mine they had the adhesive on edge beside the contiboard but the edge trim was in a totaly different spot so look about in store and its a great bonus feature for the cosmetics,also hides the edges of the glass if it aint 100% square