Frankly, the Su-35S will not make it to the MRFA trials at all. the IAF is almost 100% sure to ask for AESA as a mandatory requirement of all the fighters participating in the MRFA tender. Even if we assume that Sukhoi offers the Su-35S with the Su-57's AESA or some other AESA radar, it is likely to be very immature, having not being integrated till now. Irbis will not interest the IAF when comparing with the AESA radars that all other MRFA candidates bring to the table. Even for the Su-30MKI upgrade program, talk is now that the indigenous Uttam AESA will form the baseline on which an indigenous AESA radar will be offered to the IAF..reportedly the IAF wasn't too keen on going with the Irbis in place of the Bars on the Su-30MKI.
F-15EX with a GaN AESA radar and GaN EW suite is possibly the best of the lot on offer. And as Lord Of Gondor already mentioned, the 20,000 hour service life is truly insane. But it'll also be the most expensive one overall perhaps. The likely acquisition cost of a F-15EX would be in the range of $90-100 million flyaway or possibly even more. With all the ground infrastructure, spares, logistics, etc. that need to be set up for a fleet as large as 114 fighters, it'll be the costliest fighter in the competition.
Another big thing is the fact that with 260 Su-30MKIs and 59 MiG-29UPGs, plus 12 more Su-30MKIs and 21 MiG-29UPGs on the verge of being ordered, a very large part of the IAF's fleet is of Russian origin. IAF may not want to order what may well be it's last large import, with the Russians.
Price wise, the Russians win on acquisition cost but with life cycle costs, they almost even out or end up being costlier.
AIM-120C7 or AIM-120D may well be excellent BVRAAM missiles, but with Meteor coming with Rafales, Astra Mk1 having entered service and Astra Mk2 about to enter trials this year and SFDR based BVRAAM after that, getting the latest AMRAAM variant isn't the big carrot it once would've been. AIM-260, yes now that would interest the IAF.
The best option remains to go with 2-3 more squadrons of Rafales and end this MRFA contest once and for all. 4-5 squadrons of Rafales with large stocks of Meteors, Scalps and integration of indigenous weapons such as the Astra Mk1/Mk2 and SFDR will give the IAF more than adequate breathing room while Tejas Mk2 and AMCA are developed. Hopefully the IAF can then go with the ORCA derivative of the TEDBF naval fighter for the Indian Navy.
Indigenous upgrade program for the Su-30MKI proposed by HAL