Superficially can suggest they take a look at the Audio Technica product line. They have a variety of options at a variety of price points and overall (while there is a range of 'quality' in what they offer) AT quality (compared with other product at specific price points) is relatively . . . OK. You can get cheaper and you can go a lot more expensive but Audio Technica is a good place to start a review to see the type of options available
That said I doubt that looking at a range of what is available is going to be all that helpful.
To even start limiting options I'd want a lot more information. (rather obviously budget is a primary consideration) What they are trying to accomplish, very specific goals, is important.
If the choir is going to be in motion, or if the choir is going to perform in a lot of unfamiliar venues that do not have installed sound reinforcement then wireless can be a very functional, even an 'only' choice. Additionally if the church group rents a facility for which they need to supply their own sound reinforcement then wireless mics on the choir can be an efficient choice. If they are primarily interested in sound reinforcement in a fixed location: choir as motionless as most choral groups I've seen, performing in the same venue more or less constantly then using wireless reinforcement with the idea that it is more convenient to install and deploy is something that needs to be reinvestigated.
The space in which the choir is housed, the space they are addressing, whether they are looking for parallel reinforcement and recording, whether the recording is to include video, the size of the choir, prevalence of soloists, type of accompaniment, even type of HACV servicing the venue are all significant variables.
A simple and cost effective (depending on significant variables) approach can be Decca Tree (or variation) Three omni mics addressing choir in inverted 'T', more or less, if Choir has director, centered on director, at least as far off the floor as directors ears.
For less then $600 you should be able to pick up 3 omni condensers, suitable for either hanging or installing with booms and VHF receivers and transmitters for the mics The VHF wireless systems are not going to, theoretically VHF systems (anything below TV channel 51) should not be effected by sell off of analog bands (but not a lawyer don't play one on TV and what's going to happen with 'airwaves' from here on is anyone's guess) be effected in same way UHF systems might.. Once you move away from handheld or headphone pretty much any mic can be adapted for wireless. Condensers requiring phantom power impose additional complications a reason which is why small lavaliere style mics that can be powered via batteries on transmitter packs are attractive options with wire less systems
So the three mic system includes AT899 omni's, ATW R250 paired to ATW T201 (roughly $85 for pair) . . . Throw in a couple of boundary mics (addition cost and T/R pairs) and you've got a lot of coverage without excessively complicated or even intrusive set up. Placement of omni's and boundary while not trivial is less problematic, in some ways, then other mic choices.
Standard disclaimers are: 1. Have no connection to Audio Technica 2. This is not necessarily a system I'd recommend for any specific application . . . But simply provides some specific part #'s to start the investigation
