The 27" is a nice size increase of the 21.5... but if you're sure you'll be happy with the 21.5 then OK.
Fusion drive minimum is a must if you don't want dedicated SSD. Bare in mind... the 256GB SSD is the same price as the 1TB fusion drive and then everything on your primary OS drive will be nicely quick. External storage is very cheap now, so you could add an external drive or two or more if you wished for more than 256GB storage... by the sounds of your use, you don't need a primary OS drive greater than 256GB.
Good choice on 16GB ram... OSX loves ram and like you say, on the 21.5 it's not user upgradeable (it is on the 27, however).
For your use, the base dual core i5 would probably be fast enough for you... but the quad core is so little extra it'd be silly not to go for it... but then you already plan to
21.5 - 2.7 - 16gb - 1tb fusion / 256gb ssd = 1369
21.5 - 2.9 w/ DGPU - 16GB - 1tb fusion / 256gb ssd = 1519
27 - 2.9 w/ DGPU - 8GB - 1tb fusion / 256gb ssd = 1609 (user ram upgrade = 40-50)
You were already considering the middle option at 1519... given that the 27 is only 90-140 more expensive... I would HIGHLY recommend this upgrade.
Of course you have the external monitor option as mentioned above... but I get the impression that isn't what you're looking for and would prefer the self contained unit?
Having used 2560x1440 minimum for a long time... I would be hard pressed to go back to a 1920x1080 screen... you can do a lot more with the larger screen & it's easier to, for example, have a web browser window and office document open side-by-side - the smaller screen is too small for that to be comfortable.
To put it in context... you kept your last PC for 8 years... these are built well so could easily last as long or longer... let's take a look at the figures over that time.
Basic option = 1369
Recommended upgrade = 1609
240 difference (with the second option, you can try it with 8GB to see how you get on an upgrade at a later date if need be)
Over 4 years... the difference is 5 pounds / month and that's only half the time you kept your last PC.
To throw a massive spanner on the works... you should get down to your local apple store and take a look at the difference between the normal 27 screen and the retina screen.
Relatively, for what you get - the price difference is tiny... it's really not that much more money and the screen is absolutely gorgeous. Even the office documents will be nicer to work on with this screen, hehe... let alone when you look at pictures or whatever
The base 27 retina with 3.3 processor, 8GB ram (also user upgradeable) and 1tb fusion drive or 256gb ssd is 1759.
Basic option = 1369
27 retina = 1759 (plus 40-50 for ram if need be)
difference = 390
or just a shade over 8 pounds / month
I think it's worth it... take a look in-store and decide for yourself... make sure you have a look before you buy.
The fusion drive works well... I have a 3TB fusion in my 27... but I would rather have had even "only" a 256GB SSD... it's just the price difference was much greater when I purchased.
Don't even consider the non-fusion spinning platter drive options... they're too slow.
Also, don't know if you're preferring the mouse or trackpad. The apple wireless mouse is HORRIBLE... the lag on it is the worst I've come across. Check out the trackpad, it works well.
Many thanks, will try the bundled software first then. As for the retina display, the 27" 5k imac is to big for my work area.
Are the non retina diplays really that bad?
Thanks
They're not bad at all, far from it. It is just that once you've seen a 5K screen there is no unseeing it. They're absolutely splendid.
Exactly... the normal screens are good too... it's just the retina is that much better.