Well, I have this cheap Chicony brand keyboard (made in China) which I got along with my 1st machine. It lasted 6-7 years thru fairly heavy use. As far as I remember, the price that time was not more than Rs. 200! It had a great "feel"... even my MS keyboard does not feel that great compared to it! Thats value for money!!
In comparision my iBall was totally unsatisfactory throught and went stone dead as soon as out of warranty.
So brand does matter a lot!
If you want a really long lasting keyboard, consider a TVS mechanical keyboard. They are supposed to last for eons. I belive they are noisier than membrane keyboards though, and cost more.