It's the right size. It's been through plenty of miles but it's in good shape. The cogs have some wear on them. It's 54cm and I'm 5'8" nearly 5'9". The guy I'm getting it from is similar build and has used it for a while, but he prefers chromoly. In fact, I pretty much get all my advice from him anyway.

He he said to get some new tires but the wheels were upgraded. It just seems logical to get a different bike for near what I would pay for decent wheels. Plus I can experience some variety in the material. So far I've ridden 30ish miles on an aluminium frame and fork. I think the older 105 set is similar to modern tiagra so they are pretty similar with the exception of some higher quality parts.