Processor wise the difference is barely there for the average user. 2.7 to 2.9 is a jump that you simply wouldn't notice doing what you describe, at least IMO.
Where a performance boost might be apparent is the fusion drive. I've never used one specifically but do have experience with SSD's that can translate a bit. Assuming it works the same way SSD's do you won't see a performance increase in the sense that the mac can render or otherwise process things faster. That's dependent on CPU, GPU, RAM, etc. However you will get a FASTER overall performance. Opening applications, start-up and shut-down time, etc.
Macs are pretty fast in general, my 2011 iMac can open photoshop CS6 (without an SSD) in about 15-20 seconds (vs my macbook with an SSD doing so in about 5-10) so it really depends how much speed you want to get out of your machine and if that is worth the extra $200.
Certainly though DO NOT do it for the sake of the extra processing power. That is basically a negligible amount considering both are still going to be i5.
Either way I personally would wait a bit. New iMacs could be coming in October or November so they might be worth grabbing or you might be able to get a refurb model.
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thanks maflyn!
I haven't read yet about those fusion drives. I appreciate why 7200 rpm would be better than 5200 (or 5400) but...need to get some idea re that fusion thingy
Fusion drives are basically apple's combination HDD and SDD. They "move" the applications you use frequently (as well as the OS files I believe) to the SSD portion in order to have them open quicker and feel snappier, as they would with an SSD.
