the best are no doubt ibm A, T, and X serials.
not only because of ibm's quality, but also its after-sales service which definitely most important to end-users.
as for toshiba, i just want to say i don't believe its reputation because some of its product line use desktop cpu instead of mobile cpu, for laptop these two kind of cpu's performance are totaly different. and of course mobil cpu will cost producer much more.
why should i believe such a company which, in order to reduce cost, intent to cheat its customers?
in fact, DELL TOSHIBA ASUS ACER WINBOOK COMPAQ all have products of desktop-CPU before Intel warned them. If they can controlled the CPU temperature in an acceptable range, the CPU performance of desktop is much better than laptop. If evaluate all the same-speed-laptops, Toshiba got the best performance.
As far as i know, Cursoe is the next generation mobile processor, used mostly by Japanese computing manufacture. Actually, I am quite interested in models equipped with Cursoe. I guess there is no heating problem with that because of its different design from Intel series.