J-7, J-8II and Q-5 are relics, hopelessly outclassed and outgunned by assets found in its potential enemies, which is why the J-10, J-11 are stepping in, and in the short future WZ-10 take up the role of Q-5 (roles that Q-5 performs now are either taken up by multi-role jets or attack helicopters). PLAAF keeping them around is because they as an organization is also in the midst of major transition, unfortunately the number of J-10 and J-11 are dictated by how many engines they can buy from Russia.
That said, the only advantage - at least in Chinese perspective - is that they're "all MIC", the sourcing problem at least not as acute...in the case of JH-7, they try to make it as the cheaper alternative of the Su-30MKK, capable on some roles but inferior nonetheless.
India? Their logistics is nightmarish enough already - if and when a fight stretches, it'll boil down to how they keep up with the attrition whether it's lost in combat or wear-and-tear.