I'm curious about EPGY since they don't offer a demo or free-trial (that I can find). Other than it being a bit dry, does the material seem thorough and well-plotted?
Yes, EPGY OE Math K-7 is very 'thorough and well-plotted' (which is rare), and somewhat 'dry' (no 'dancing bears'), which worked just fine for our DC. The only piece of entertainment is 'computational races' at the beginning of every lesson (which may be skipped). The lectures used to be read by an older gentleman, a Stanford professor, the creator of EPGY.
The 'gifted' setting reduces the repetition noticeably, and switching it on helped at the time.
I was not aware of the 'review exercises control'; your SSA should know about this.
You may move your child's grade placement by 1/2 grade up or down at any time (without asking SSA). This is particularly useful. (EPGY's guideline is that ideally your child should be getting about 70-80% problems correct. This has been discussed on this forum earlier as related to counteracting perfectionism.)
We tried several other well-known online math programs at the time - none were particularly useful. (DC was about 7, but had decent math skills.) DC uses AOPS now and the plan is to use all that AOPS has to offer.