I was considering a T1i until I was offered a MINT Canon 20D; having had very little use. The 20D is about 7 yrs older than the T1i. Should this be an important concern? The T1i has double the mpxls of the 20D. How important is that? If I had to make a choice between these two specific cameras, what would be your advice and why. Please....consider only these two and NO other options for now. Thanks.