Not sure the route will set the thread alight, but I thought I'd post mainly because it was my first redemption and I learned a few things along the way that might interest less seasoned users.
Heathrow-Palma (Majorca) for May 2008. 2 adults, 2 children. w/e flights.
Depart just before final week of school term, return two weeks later at end of half-term. Popular time to travel, and EasyJet, Thompson, etc. are showing suitably high prices.
bmi online redemption showed no availability, but thought I'd call up and ask anyway. Was told it was full, but they'd put a request in for seats to be released. Was also told that if the seats weren't released but I made Gold in the near future then call back as they would then almost certainly get me on (probably made this comment as I was high-ish Silver).
Anyhow seats were released and (despite a bit of minor confusion and annoyance relating to me trying to change the timing of the outward flights) they were ticketed shortly afterwards. Very pleased as LHR is a much better airport for us, the actual flight times are better, and I'm looking forward to being on a 'proper' plane.
So the things I learned are:
1a) It's worth calling even if the online system shows no availability.
1b) Especially (it seems) if you have Gold.
2) Children under 12 go at 75%, while the 'budget' airlines seemed to want full price. That seems fairer in some way and I like it.
3) Request separate outward and inward flights so you can adjust them more easily.
4) It seems very cheap on cash+miles. Even if I'd have had to purchase all the miles to do the redemption from the bmi site it would have compared very favourably with the pure cash price from the other airlines.
5) It makes up in some small way for having to be away from home to earn the miles.