This is coolbert:
Here with some from a variety of sources and thanks to the tip from Dee some LESS THAN sanguine appraisals of the Russian Su-57 warplane.
"san·guine - - adjective 1. optimistic or positive, especially in an apparently bad or difficult situation."
1. "Russia's new Su-57 'stealth' fighter already looks like a disappointment"
2. "China's and Russia's stealth fighters don't stand a chance against the F-35 and F-22"
3. "Why Russia's New Su-57 Stealth Fighter Might Be a Giant Waste of Time"
4. "India Might Finally Terminate Their Stealth Fighter Program With Russia"
LESS than sanguine each and every instance. The Chinese J-20 also not a multi-role combat aircraft [MRCA] able to perform a multiplicity of missions in addition to air superiority. J-20 the primary mission will be to engage American tanker aircraft with an air-to-air missile at long range. So it is speculated.