Seriph
If a FSS is very badly underfunded, (such as BA's NAPS for instance) and the company goes bust, then those who are in retirement are looked after before a penny piece is allocated to those who 'were' in employment. That is set in law, although there have been calls for the law to be amended.
So in the possible case of BA going bust it is very likely that those currently in employment would only recieve a very small proportion of their contributions returned, if anything at all.
So Money Purchase schemes do have the advantage of security in that nobody else can benefit from your contributions.
Regards
Exeng