Hi ladies and gents, I've been thinking about upgrading my Maverick iMac 27 inch to Yosemite. Is that a good or a bad idea? Will it get slower, are there any big problems i should be aware of? I bought the iMac in 2014 but i think it's a late 2013 model (if i'm not mistaken). It's before the latest retina relases. Thanx ahead!