Offering a slightly different viewpoint to those of G-KEST and VP959.
The PFA and BMAA have both, with the odd glitch, done a very good job for their members. Two large fleets, lots of pilots flying cheaply, a whole raft of hardwon privileges, not to mention Telford and Kemble show that very clearly. Both have from time to time had "bad patches", and it's fairly clear that just at the moment PFA is having one.
However, why is BMAA as successful as it is? - to a fair degree through comparing itself to the benchmark that is the PFA. Why is PFA looking at type-approved microlights? - because the BMAA has made such a success of them.
My point here is that a degree of overlap and competition is actually very healthy. Both are businesses and members organisations. In that capacity, they do compete to an extent - but the only thing that they can really compete with is standards of service.
If you had a single organisation, and no competition, there would be far less drive to ever-better standards of service (or not to charge more than the other mob) and you'd, well, get something not dissimilar to the CAA.
To give a simple example, let's say a new 3-axis homebuilt microlight comes along. With a single organisation, the Chief Engineer could reasonably say "well, it's a lot of effort to approve, our members already have something similar to fly - there's little benefit in pulling the stops out for this". With competition it becomes "we'd better do a good job on this, otherwise it'll go to the other organisation, and they'll have the long-term airworthiness and membership revenue - too many of them and I'll be out of a job".
Without doubt, this level of competition is very stressful to the staff and committees of both organisations, and to a lesser extent to people whose recreational or professional activities straddle both organisations. But, to UK light aviation as a whole, it's very healthy. Arguably if either organisation started taking an interest in gliders or SLMG as well then we'd probably see both even more stress for the professionals, and benefits for glider pilots too.
G
Stressed GA professional who enjoys his cheap flying.