I came across the closet components Target has while browsing there one day. I don't know the name of the pieces, but I was quite surprised by the quality of the drawers and glides. They were sold as stacking units, but I'll get DH to mount them. They had side metal slides for the drawers and a double drawer was $39 I believe. I haven't done more research to see if they sell them on line also.
I really like Ikea's PAX / COMPLEMENT systems, esp. with respect to their drawers. IKEA closet systems come in 2 depths - 14 inches and 22 inches. The 22 inch deep units allow for much more functional drawers than I've seen elsewhere, given that most closet systems are anywhere from 14 to 16 inches deep. The IKEA organizers are cheaper than their competitors as well.
I know nothing about Elfa. I have not taken a look at what Target has to offer.
In our mud room, we installed Ikea PAX / KOMPLEMENT closets. They are 95 inches tall, which means we had just enough room to stand them up, once we assembled them on the floor. The height means we can hang a one-piece work jumper inside, if we wish.
I like the flexibility of the Ikea closets. No drilling into the carcass of the cabinet, leaving nasty holes. I like the variety of available shelves and drawers and clothes rods and containers.