The website still slows my computer down to a crawl - both a Dell laptop I use for work and a Surface Pro I use at home.
Also half the time I'm trying to do a search I can't move the date calendars forward or backward.
It was bad enough yesterday that I gave up and booked my trip on WN instead (it was to Dallas so still nonstop and just as many schedule options). I have no idea if WN was more/less expensive as I couldn't ever complete a search on DL.com.