Of your two choices, i'd go with the dell
Having said that - Ausus has the highest rating (least problems) followed by toshiba. If memory serves me right del was about 5th and HP lower (didn't check Sony as I do not buy sony products unless arm is twist rather forcably.
Me @ work Dell, but it's the busness model, 2 toshiba's for home.
For video editing, as stated above a lot depends on the program. If dealing with large video files, memory and cpu speed may be more important than the # of cores. VOB files tend to be 1 gig or less, while a single blu-ray file can be as large as 35 gigs. If max file size is under the 1 gig than 4 gigs is fine. Down stream it would probably be better to go with the 4 cores and you can alway increase memory. Unforanatly laptops are not normally over clckable so you are stuck with the proc stock speed. - But there needs to be a 15 -> 20 % diff to be noticeable.