Synthetic approaches, in and of themselves, are not bad...however, they are very susceptible to differences in the environment, which means the proprietor that lets it get humid or that does not make a regular habit of having staff sweep the approaches is inviting problems.
My experience on a house that switched to synthetics was that they were super-slick for the first few weeks and many were actually trying to dampen the heel to get some stick...this was, however, before the days of switchable heels.
Wood can get just as tacky...I ran into that on a pair this weekend. Rest of the house was fine, but one pair had my number and I absolutely could not find a heel/sole combination that would work on that pair.
On newly installed synthetics, expect a lot of experimentation on the condition because some shots that are playable on wood become very unplayable on synthetics until the oil distribution is tweaked. The slick will seem slicker and the dry will seem like monster dry.
The best of all possible worlds is if the proprietor is keeping the wood approach and just changes out the lanebeds.
