Well here is the unbiased comparison between JF-17 and Tahas here is few points
JF-17 thunder
1. Already in production line and developing year by year . Multiple version developed.
2. Already exporting to other countries and in talk.
3. Cheaper
4. Chinese technology but production factory in pakistan only.
5. Good speed and handling.
6. 1st line air defence fighter jet.
Although it has some drawback also.
Tejas MK-1
1. Stealth quality, light wait,
2. Very good in Handling, cutting edge , state of the art technology.
3. Multi role , but 2nd line of defence
4. Going to equipped with astra bvr
5. Unique shape, better speed, angle of turning and stability.
6. More life and cheap maintenance.