Well its the second half of the season already so lets rate This years up and coming.
In my opinion:
Kobayashi(under F1 rules he completeled less then 3 races in '09 so hes classed as a rookie for '10) - Clearly the best rookie by far at present, hasn't impressed much up untill recently though but to be fair the sauber wouldn't even last half a race distance now that it can hes been scoring plenty of points, Valencia showed hes got future potential and living up to hes '09 promise.
Petrov - Been Completely owned by Kubica, but has shown promise here and there but right now hes looking out of place being in F1 and he doesn't really seem to be improving much, he needs to get some points asap.
Hulkenburrg - Isn't doing too bad, i would say hes the 2nd best rookie this year, still needs alot of improvement but that will come with experience.
Di Grassi - Allthough hes been staying with Glock most races even beating him in others, the car is too slow to see anything.
Senna - Can't really see anything with that car but is having a good battle for chandhok seems very even
Chandhok - As said above, its very even in HRT but the car is much too slow to see anything because there never actually racing anyone just trying to finish.
In my opinion:
Kobayashi(under F1 rules he completeled less then 3 races in '09 so hes classed as a rookie for '10) - Clearly the best rookie by far at present, hasn't impressed much up untill recently though but to be fair the sauber wouldn't even last half a race distance now that it can hes been scoring plenty of points, Valencia showed hes got future potential and living up to hes '09 promise.
Petrov - Been Completely owned by Kubica, but has shown promise here and there but right now hes looking out of place being in F1 and he doesn't really seem to be improving much, he needs to get some points asap.
Hulkenburrg - Isn't doing too bad, i would say hes the 2nd best rookie this year, still needs alot of improvement but that will come with experience.
Di Grassi - Allthough hes been staying with Glock most races even beating him in others, the car is too slow to see anything.
Senna - Can't really see anything with that car but is having a good battle for chandhok seems very even
Chandhok - As said above, its very even in HRT but the car is much too slow to see anything because there never actually racing anyone just trying to finish.