I have also noticed how much more pleasant the working atmosphere has become at bmi. Rosters should average out at 10 days off in every 28; for my last few I have generally only had 9, so I'm now on a larger block of days off to make up the numbers.
As already posted, narrowbody pilots are usually rostered a 5 day block of standbys in every roster period; this is almost always changed to flying (not necessarily the whole block, but some of it) before the standby block actually starts. On the whole I would estimate I fly about 90-95% of my standbys; airport standbys, on the other hand, I probably only fly about 2/3 of them.
There is only one destination in the route network that I dislike flying to; unfortunately so do most of the pilots, so it is rarely possible to swap it away!