Thanks to everyone for the quick responses to my question. I feel much better making a decision about this and intend to discuss it with my contractor further now that I am aware of some of the pros and cons. In the specifications, it does not call for anti-seep collars on the PVC stand pipe system, just on the 6" overflow pipe. Unless they have a good idea for fabricating one like the rubber one Theo mentioned, I may opt for the increased trouble of working around not having a stand pipe, since my needs to use one have been non-existent thus far. Although it does sound like they provide a nice system if and when they are needed. I am still curious if anyone can address failures with the valves? I guess it could be that they likely outlive the installer so no one has had any problems with these yet.
Thanks again for all the insight.
