Myself, I used it only once near the end, because I knew it would end and figured I should while I could. Despite the limited selection of bricks/colors I am hugely satisfied with my custom set, and really enjoyed the quality packaging too.
Many of the pieces I got were new, from after I stopped buying LEGO sets due to lack of room, so I was very pleased to be able to get my hands on large numbers of them without resorting to Pick-A-Brick or buying a lot of unwanted bricks along with them in standard sets. (And I do plan to possibly use Pick-A-Brick now.)
I thought it rather strange and counterproductive that after I told them not to send instructions, to save paper, they included this huge-o letter "apologizing" for not being able to send instructions, plus a huge list of bricks with color pics of each one... defeating the point. Why not just one sheet summarizing my choices and listing the names of the bricks, with perhaps a URL to go online to see the pics? Or at least they could have offered that as an option. But no big deal.
It also took far longer than the supposed 3-8 business days to ship, but that's perhaps because I ordered in the final days and maybe a lot of others did too, so they probably had a backlog.
I'm not sure if I would use it again if they brought it back, but I would try to. I must admit that Pick-A-Brick makes it a little superfluous, but convenient. And I would definately be more likely to use it if they offered a better selection of bricks/colors. The new "standard LDD mode" selection is a good example of what I'd prefer, but of course I understand financial reasons this isn't practical.
Edited by bonesiii, Feb 08 2012 - 12:39 PM.