I have been flying BA for the last two years but got tired of their misterly ways with the type of tickets my company buys - 0 tier points and 25% of miles flown on offshore fares.

I am now switching to AF/KLM and already have miles on FB and OnePass both recently and also from the past. What I need some advice on is which program I should collect miles on in the future. Note that I live overseas and am travelling to the US quite a bit but will also be travelling within Europe. I will mostly be flying out of AMS - is it better to collect all miles on OnePass or FB whether I fly KLM or Continental? Which has better upgrade possibilities? Are the programs such that it doesn't matter which I use as the benefits crossover to the other airlines equally?

Finally, does any know if I can collect miles on Air Astana?

Flying Blue is an unmitigated disaster. A quick peek at the FB forum will tell you all you need to know. No points for cheap fares, no upgrades from anything but full-fare economy (Y or B), and worst of all the incompetence of Flying Dutchman and the contempt of F+ seem to have met somewhere over Belgium in a kind of customer-averse perfect storm capable of driving away even the most adamant KLM supporters (like I was). Disclaimer: former F+ members don't seem to be notice much difference.

The one upside is that you'll get lounge access if you have a European address, and the newly-refurbished Crown Lounge in AMS looks to be quite nice. I'm also around 50/50 on long-haul op-ups flying on high economy fares, but this is due to careful planning.

On CO, you'll get domestic US upgrades. If you're doing much domestic flying (or connecting), go with CO for the upgrades, higher mileage earning, and better access to long-haul upgrades (providing they still do the hokey-pokey or something similar).

I'm one of the former F+ members who is happy enough with FB. The FD people lost some important benefits, but for most of us F+'ers nothing significant changed except we need to fly a bit more for top level elite. But most of us don't have a problem with that.

Some of our folk have reported complimentary upgrades on NW, but I'm not sure about CO. I get comped each year to CO Gold, but I've only flown them once in the last 10 years. Just make sure you have Skyteam Elite Plus to get lounge access everywhere.