a couple of issues here. First, the US never releases the true performance figures. However based on various sources:
1. the F-35 will have a longer range than either the F-16 or F/A-18;
2. the F-35 will have better performance, acceleration or maneuverability than the F-15/F-16/F/A-18.
http://www.flightglobal.com/news/art...hornet-382078/
currently, only the F-22 can out perform it, but the F-22 is a dedicated air superiority fighter while the F35 is a "jack of all trades".
3. yes in "stealth" mode, its payload is limited, but in non-stealth mode, it can carry a bigger payload than the F16 or F/A-18. Stealth gives you more options, in a high threat environment, the F-35 can be in and out without being detected, while in a low threat area, it can carry all the bombs you want.
lots of critics out there with an axe to grind, but looked at objectively, the F-35 is a great airplane.