been having the same problems with lovefilm myself :/
i think the reason ppl seem so bothered by this is that they've had such a good service from them up until now. theyve really gone from providing a top class service to being unbelievabley bad
i dunno how useful the following info will be but i signed up to trials on 3-at-a-time services from screenselect, dvd365 and blockbuster and also cut my lovefilm list down to match 10 disc queues on all 4 rental services. On an even footing, with a fair amount of what i'd consider low demand titles (0 new releases or anything rly made in the last 3 yrs) I found the following:
from having built the selections up on sunday night:
lovefilm sent me 1 dvd on monday, arrived tuesday. choice #3 out of 10. still no sign of the other 2 discs i guess as part of this new game theyre playing to try and put themselves out of business.
screenselect sent me 3 dvRAB on monday, 1 arrived tuesday, 2 on wednesday. choices #3, 9 and 10.
blockbuster sent 3 on monday, 3 arrived tuesday, choices #1, 2, and 7
dvd365 sent 3 on monday, 3 arrived tuesday, choices #2, 3, and 5.
Obviously this isnt a flawless test of the services but take from it what you will.

i think for me personally I just have to decide between dvd365 and blockbuster in the next few days before i cancel lovefilm
