So for a few months I've been shooting with a Sony a700 and it's been great. However, with small lens upgrades and additions here and there, I've noticed how limited and expensive the lens market is for the Sony Alpha mount. To make a long story short, I have a buyer lined up for my Sony a700 and everything else and would love to go BACK to Nikon (former D60 shooter). In comparison to the Sony a700, which Nikon is just as similar? I'm trying debating between the D90 or the D300.... is the D300 worth that much more than the D90?