I think you guys have it wrong. Although out of VT-4, Altay, T90MS, and Oplot-M, Altay is definitely the best and also so much more expensive, T90MS is better than VT-4 and Oplot-M. Oplot-M and VT-4 are quite similar level overall but Oplot has better protection against penetration round while VT-4 has active protection system to protect against missiles which Oplot cannot. Otherwise VT-4 firepower may even be slightly better than Oplot. Oplot is more expensive I think. However T90MS is better than both and Altay is one level above at K2 tank level.
For considering price, then VT-4 and Oplot are best choices but Oplot is not quite available and VT-4 has more chance for future modifications and easy improvements. Engine output depend whether Pakistan's VT-4 will be 1300hp or 1500hp which could be much more than Oplot but Oplot is also smaller and lighter than VT-4.
For equipment inside the tank, I risk betting VT-4 should be better than Oplot-M which is 2000s equipment and some new stuff introduced after 2010.
VT-4 and T90MS in theory is very close with some slightly better in certain areas but both are very new tanks upgraded from older stuff like combined Type 96B with Type 99A and T-90 with T-14 improvements and in between improvements. However I think T90MS is better because it achieves everything VT-4 has with smaller size and lower weight. For tank's mobility and access for difference terrain this is actually incredibly important. T90MS can also add active protection and modify armor. Price seems to be slightly higher than VT-4 though.