I use a wall, but mainly because I don't have any floor space or a table large enough to accomodate anything larger than a crib-size quilt! Anything crib-size or smaller I use a table. I tape each layer down around the edges with blue painter's tape to keep it flat and smooth, then pin with straight pins and homemade "Pinmoors". (I don't like safety pins for basting, I bought two different kinds of "quilting" safety pins and they were so thick and dull it was tough to get them through the fabric, so I gave up!)
If I had more space I'd rather use the floor or a table for everything. The wall causes a the top part to be tighter and the bottom to be kind of baggy and I have to be careful when pinning to smooth it out - I end up un-pinning and re-pinning a lot because I'll get ripples. Sigh!