Assuming that FL credits are treated exactly the same as RR 1.0 credits, there is a hitch to be aware of. RR 1.0 credits expire if they become 2 years old before you reach 16 credits. You can transfer new points to top off the 16 credits, at 1200 points per credit. However many infrequent low-fare travelers will have trouble earning points quickly enough to avoid expiration. One solution is to buy the points ($25 per 1000, or $150 for 5 credits), but in general you are screwed unless you were already close to 16 credits.

So my recommendation depends on whether you can put your FL balance close to 16 credits at the time the programs merge. My guess for that date is January 1, 2012, because the mechanics of merging are easier at the start of a calendar year.