1. Performance :--- Both r almost same though for sequential read writes the WD will be a bit faster as it uses higher serial density platters.On the other side the access times will be slightly higher in WD
2. Reliability---- A draw of luck but histirically speaking seagate is more reliable
3. A.S.S -- WD is better considering its door to door service that also with a TAT of 7 days.But remember seagate RMA is also quite good.
Adding some more points
4. Build Quality---- Seagate is better from what I have seen with the above 2 drives.
5. Cooling ---- WD runs a bit cooler than the seagate & has a noise profile also which can be tuned for performance/noise as desired by user. Its know as AAM.
6. Cache--- 32MB cache is not much useful though present on the cache.
7 Price --- Seagate is slightly higher at arnd Rs 8 per GB compared to Rs 7.5 per GB on the WD.
All in all for day to day uses both will serve u quite good.
Just pick up whichever u like and I guess u wont be disappointed.
If u ask me..I have a 7200.11 and picking up the 6400AAKS also in a day or two

....and have seen one 6400AAKS in action sometime before as well. TO ask which one is better will be totally unfair as both have their own advantages

...All in all relly good competitive drives
