I've rejoined Nicheflix on the two-out plan, so now I'm a member of four different online DVD/VHS rental services. I had to go with them, because they're the only one to rent King Kong (1933) on DVD. Nicheflix specializes in multi-region DVD rental.
I still have over 300 movies in my Netflix queue, on the 5-out plan, mainly from the book, 1001 Movies You Must See Before You Die
I use Blockbuster Online's 3-out plan for mainstream hits, because it seems that's all they have available. Out of 30 in my queue, only six are "available now".
I use Facets Multimedia for VHS movies that are rare or out of print.