MacBook Pro Retina i7 2.6GHz quad (Haswell) vs iMac i7 3.5GHz quad for LPX?

Question

Hi guys
I have decided that despite the fact I love my current six-core Mac Pro, it's time to move onto something with a faster internal bus, SSD, and faster RAM… and the new "pot plant" Mac Pro is out of my price range.
I need to have a computer for live work, so I am either looking at getting a Mac Pro Retina 15" 2.6GHz i7 (the highest spec Haswell), or an iMac 3.5GHz i7 (the highest spec iMac) + a more basic MacBook for live use.
Really wondering how the Retina MacBook and the iMac with the above specs would compare, performance-wise. It seems scary to be moving over to either of them from a six-core 3.33GHz processor in the Mac Pro, but I am pretty confident that in a lot of ways, such as latency, either of these will actually perform better than the Mac Pro does.
I would love to hear your thoughts, though, on how the MacBook and the iMac with the above specs would compare.
I use quite a lot of virtual instruments, generally run Logic Pro X (although Pro Tools is also seeing a bit of use), and my projects are pretty large. I use BFD3 and other drum plug-ins with a V-Drums kit, which requires really low-latency performance.
How would these two computers compare in terms of heat generation? Would the MacBook get very hot under extreme workloads?
And in terms of general performance - say, track-count and for single tracks with a software synth (say Diva) and a few effects, played in realtime, how might they compare?
Lastly - will all the heat and tiny fan on the MacBook mean that it is more likely to die after a year or two of use? (One of the things I love about my current Mac Pro is that I can replace any part that dies, quickly and easily - and in any case the processor is cooled by a giant fan!)
So - would really love your thoughts, especially if you are using either or both currently.
Cheers,
Mike

Answer 1

I owned the imac and then returned it for the 2.6 MacBook Pro. After using both there is a noticeable speed difference between the 2. Not a huge difference but there is certainly more lag using the MacBook Pro. I found that lots of the lag went away when I attached to an external display though. At the end of the day I think you just need to decide if you need the portability or not. At first I thought I would keep the imac and then get a cheap MacBook Pro to use on the road but the thought of having multiple Lightroom catalogs sounds very annoying to me. Plus all the transferring back and forth. I will say also that I've been getting a lot of freezes in Photoshop on my mbp and weird errors like the sleep wake failure error some people are talking about when connected to a USB device. I didn't have any of these problems with the imac