Should I buy Nikon d7000, I'm so worry about the problems that other users have experienced

I'm planing to buy nikon d7000 as my 1st dsrl. However, I'm still worry about the problems that spread around the forum such as spoiled oil on sensor, and focus system problem. My question is that will all of these problems happen on the decent product (recently produced), I believe that Nikon would have fixed it, if it were hardware flaw ! Please help me guys ! if you know about this scenario . Thank