i've had a LOT of laptops.
i tend to settle on compaq/hp ones, because their phone support for RMAs is a lot better than dell and they tend to cost less than dell. plus they dont look as dull.
the dells ive used and had, well for one thing i dont think i've ever seen a dell in the 15 + years i've used computers that i would ever say felt "rock solid" not like an ibm.
toshiba's business tecra lines, are solid. the consumer one is just as bad as dell in flimsy plastic mcdonalds toy like ness. then again most consumer laptops are in general (there are like 4 companies that build all of them anyway).
toshiba consumer tech support is quicker than dell and a lot less time on the phone. but toshibas tend to cost more and there are never any deals. you also cant custom build a toshiba. i had to rma a toshiba ones, and they tried to give me all these options to do instead of sending it in. i knew it was dead.
and had to keep pestering the guy on the phone until he let me send it in. it was fixed in about a week. not too horrible.
HP on the other hand (my favorite for this purpose) they seem to freely give RMA numbers, so you just send it in , overnighted by them for free and get it back in like 4-5 days. its pretty nice, a lot less phone calling and hassling.
sonys are just pretty. probably a bit more solidly build for thin ones (generally thin laptops are made of titanium, or magnesium alloy, so they always feel sturdier than the larger plastic mainstream laptops). sonys do look cool, but they are really expensive. that and from what i've heard, their support is down right terrrible, and their turnaround times on repairs are god awful like up to a month.
so i guess in that case, given the choice of a dell sony or toshiba i'd sadly have to admit i'd get the dell, since you probably get more for your money and build quality and support probably are all even across those 3 brands.