Before you start comparing J-11B to Su-30MK, know there are significant differences between their intended functions. Su-30MK was imported from Russia for the Chinese navy, not air force, as a maritime strike platform along with JH-7A. It is a tandem seat fighter-bomber with the primary role of engaging surface targets. J-11B on the other hand, is a single seat A/C designed for air superiority. It serves with the air force, NOT navy. With this in mind, here are the differences:
- Su-30MK has a strengthened frame to carry extra air-to-ground payload compared to J-11B, making it a bit heavier.
- J-11B uses WS-10A engines, while Su-30MK uses Russian AL-31F engines
- A holographic HUD and 3 MFDs were installed on the J-11B as upgrade.
- New radar was installed on the J-11B, with plans to install AESA later on.
- J-11B is able to use PL-12 (SD-10) and PL-9, where Su-30MK requires imported R-77 and R-73.
I'm not going to make a comparison with Su-30MKI since it will only turn into a pissing contest.
One of the better posts in this thread, because it's based on facts and specs, not on assumptions only!
But I think if we can add more of these facts here, it would not end up in a such a contest.
One of the basic misunderstandings imo, is the fact that Su 30MK versions are considered to be strike aircrafts, but that is not the case!
Su 27s (just like PLAAFs SKs) were air superiority fighters without strike capabilities. The Su 35 and 30 MK instead were the first Flanker versions that added these capabilities, which makes them useful in the strike role as well, but still mainly designed for air superiority. That is the reason why Su 30 MKKs were added to PLAAF, although they already had similar (but less capable) versions.
J11 is based on the Su 27SK air superiority fighter yes, but AFAIK (and S10 correct me if I'm wrong) at least the B version was multi role capable too.
The heavier airframe of the Su 30 MK versions, comes mainly from the twin seat config, in WVR combats this obviously gives an advantage to J11, in terms of maneuverability. On the other hand, having 2 pilots / a weapon officer, is one of the biggest advantages of the MKK in the strike role again.
The Su 30 MKI has of course the same base as the MKK and the higher weight of the twin seat config gives him the same disadvantage in terms of maneuverability, but the key point is the different aim on the roles they are meant for!
You said the MKK was aimed on long range maritime strikes, which is possible by the fact that it is a multi role fighter, with useful radar and weapons for this role.
Indian MKI however was not meant to be a fighter mainly for the strike role, it was intended to be used in A2A and A2G! That's why IAF took the base MK with twin seat config and added features to make it even more capable in A2A. The higher weight compared to single seat Flanker versions (including Chinese) is partially countered with the addition of higher thrust engines + 2(.5)D TVC (2D TVC with a tilted angle, to provide some thrust direction in the yaw axis as well) + canards. This combo adds to its maneuverability and makes it the best twin seat Flanker version (together with the MKM) in this field and even for J11B, it will be a tough opponent here.
In BVR it gets even worse, because as you stated, J11 uses Chines weapons, not Russians, while MKI has R77 missiles and the Bars PESA radar. This combo provides MKI with the advantage of first sight, first shot and when we add the Israeli EWS and jammers for self protection, it should be clear why the MKI is considered to be a very capable fighter in A2A combats.
The twin seat config in this case is not really a disadvantage, at least against 3 to 4. gen fighters, or other Flanker versions (except Russian Su 35 and Su 34), but gives additional operational advantages as well. IAF uses the advantage of 2 pilots and mid air refuelling for long range and long endurance patrols, reportedly up to 9h!
In A2G it still remains to be as capable as all Su 30MK verions, but adding western avionics will be helpful here as well (French navigation systems, litening targeting pod...).
Basically, the MKI does what Mig 29 and Mig 27 did before, but more capable as them and in both roles.
And because I already saw such a comment, no MKI is not perfect, but is one of the most capable fighters in South Asia at the moment. MMRCA as a fighter, is needed to complement MKI in certain areas, but as a competition has way more requirements than just the replacement of fighters.
That should explain the basic differents, I guess. J11 will be good air superiority fighters, like most of the Flanker series, but has some specific disadvantages to the MKI. Mainly because the MKI was aimed on different roles and beeing as multi role as possible.