Pretty much all lipos are very good but these are older generation cells. They have higher IR and slightly poorer in performance to the currently available high end packs.

It would depend on the class you are running if you would notice the difference on track.

Whilst they are still ok to use they are IMO over rated and over priced.

If they were budget priced then they worth buying.

From what I have seen the best lipo on the market atm are the IP cells (sold under ProMatch and Orca brands plus others) or the SMC cells.