I am currently trialling all uk online dvd rentals.
So far I have only tried Blockbuster and Lovefilm.
Blockbuster were fine, and it was over the Christmas period so turnaround was to be expected. I built a large queue list, and I found the titles they sent were very much from the middle of my choices rather than the top selection. Packaging was pretty good in plastic sleeves, mosts DVRAB were pretty clean.
Lovefilm have been a lot better, they have sent my first 3 choices most times, and their turnaround seems a lot faster than Blockbuster, I also prefer their site. The DVD's aren't the cleanest in the world, and I have had to have 1 replaced, but a quick email had them despatch another the next day. The packaging is a bit weak, but once you know how to open them properly, your need for sellotape decreases.
I am halfway through my Lovefilm trial, and so far I've preferred them.
Screenselect next.