Hi, I am using MBP 17" 2010 mid model. I am not so satisfied with the performance. Performanance-wise both in general and in 3D CAD, how is the top end i7 16GB version of SP4 compared with the top end version of rMBP 15" 2015? Is it true that Apple has done something to make the SSD in the current rMBP 2015 very fast? Perhaps faster than that in SP4? We don't know when the 2016 Mac models will be out. If I buy rMBP 15" 2015 now and a new one come up in March or June, I will not be happy about it. Some SP4 users have been complaining about bugs but after some updates, some seem to be ok with it except for the power drain while sleep issue.