Interesting that you were able to pay over time, rather than as a lump sum, but each LGPS is peculiar to its own county scheme, as you know. We did receive advice from an IFA, who strongly recommended the money purchase schemes (NEST or similar). Unfortunately, these NEST type schemes are unlikely to be as generous as the LGPS when it finally comes to retirement, and is dependent on the funds value at the time rather than any formulae.
Some calculations that I made certainly show there is a considerable difference in any future value of a pension that can be drawn.
I think one thing should be made very clear to anyone looking into a LGPS, is that the employees benefits are guaranteed, but the costs and risks fall squarely on the tax payer, via the precept. It is not backed by Government, as the name might imply.