Has anyone here worked in environments where E-LANs/VPLS was used as an SD-WAN transport? If so, did you encounter any scaling issues?

The reason I'm wondering about this is that it seems like a metro-based E-LAN (which is essentially built over the local ILEC's access network, instead of an MPLS backbone) would be a pretty cost-effective alternative to a DIA/broadband combo for environments with high site density in key markets. However, I'm wondering perhaps the multipoint nature of E-LANs would negatively impact scalability.