I have a 15" 4 year old macbook pro with 2.15 processor. I was thinking that there is still some real value here. This machine is currently my main machine and i have it hooked up to a separate monitor and keyboard. So here is the questions: If I get a 13" MBP. Will I see a big performance increase over the 4 year old 2.16 or will it be marginal? Is it considered a downgrade from my 15" on an upgrade? I travel about 2 times a month with work and I carry my 15" which gets heavy. My next question is would you get a mac mini and an IPAD for travel or get the 13" MBP. Although the current 15" is nice it is heavy to carry and the real reason I want to sell is the battery keeps dying on me. I have replaced it a few times and it maybe last 6 months. Also the battery time sucks. I see the new ones can get up to 10 hrs on a charge.