Ok I could be being thick but this seems really complicated to compare. Looking at updating the 10 year old PC we have as despite SSD and upgrades it's clearly on it's last legs. Price wise I can talk the wife into £1700 so 15" Macbook Pro is possible as is 27" iMac. We probably won't move it around much so the benefit of portability is not something we will gain a lot from. The bit I am confused about is processor speed, how will the lastest 2.0Ghz i7 in the MacBook compare to the 3.2Ghz i5 in the iMac?