I think it depends on the price point of your home. If its a starter home on the smaller size, then do the big box stores. They are probably the least expensive and you could paint them yourself. If you are in an estate home...more expensive home in your area, then go to a door distributor to get a solid door instead of the hollow doors from a big box store.

Home Depot periodically (maybe quarterly) has free upgrades to solid core with Jen Weld. You can also find a larger selection of brands and better quality doors (not referring to JW, I don't know where they stand) at some lumber yards. This post was edited by snookums2 on Sat, May 4, 13 at 14:16

You can order much nicer bi-folds than what is on the sales floor at big box stores like Home Depot and at lumberyards. Ask at the millwork desk. You do not need to put bi-folds on a track - you can put them on regular hinges, which will also allow you to push the doors flat against the walls flanking the closet, so you have better access to the full width of the closet. This takes up less space than conventional doors. I did this for the master bathroom in my previous house because a swinging door would have wasted too much space and blocked a window. Large shutters can be hinged together to make bi-fold doors, and some shutter companies will do that for you for a small additional charge. Many small custom door manufacturers will make bifold doors to spec. Even if not backlit, a frosted or textured glass panel in a closet door can reduce the visual heaviness of a large set of closet doors.

Got a bid from Marvin doors $17k (Wood) and Panoramic Doors (Vinyl) $10k for a 10’ by 8’ door. Panoramic doors have 10 year warranty and customer service so far has been amazing! Seeing the Marvin door in person I was extremely unimpressed especially for the price. I like the fact that it was explained that Panoramic doors carry the weight at the bottom not the top. I was originally concerned about overall structure with such a large door. I’m finding it hard to reach anyone at Nana wall and getting a quote online is a pain.