We are looking into CA and K12 in our state for their virtual program to ease into the homeschooling mode with our oldest DS8 next year as he starts 5th grade. CA does have gifted classes, but it varies by state as to who they accept into it from what I'm told. I know here in LA, you must have already had a gifted iep designation from a public/private school before they allow you into the gifted program in the virtual school (we had to sent them the proof).
I personally like the CA programs a bit better than the k12, mostly for the elective offers and language, plus clubs ( I have a social kid and he LOVES the interactive anything whether in person or on the computer ). I have heard that CA's courses are harder and take more effort than K12 from parents whose kids have struggled after being enrolled but I am not going in expecting that for my son...I would welcome a challenge for him for a change!
However, as of yesterday I am now looking at the differences between their public school offering and their private because we may be moving to a different country start of next school year (little surprise from the military yesterday). Our DS is PG and the public school system is just not a good fit for him so we are getting our feet wet with hopefully CA, but possibly k12 depending on state limits/or tuition or both!