I found interesting information like to share with you. Talking about Su-30, Su-35, Grippen, F-22, F-35 there are nice info out there for comparison.
This shows Grippen RCS to be 0.1 square meter. Amazing for a 4.5 gen aircraft. See how it detects the 10 square meter RCS Su-30 even with less powerful radar.
I guess you all have seen the next one in the Aussie website. It is a nice one and shows based on the old data the detection range of different radars:
Again it shows the detection range of Su-35 lower than its counterpart due to lower quality RF front end (low noise amplifier and DSP together) but this only considering the illuminator is the aircraft Tx and no further illumination from ground which offsets the difference I assume.
I was looking to find RCS for SU-35 but couldn't I believe it is in 1 meter range and not the huge 10 meter of SU-30 but I couldn't, instead I found this interesting.
It says Grippin (JAS39) to be minimum 1.9 but the other site says 0.1 so probably it is skewed anyway if someone has comparisons good to provide it here