Upload & Sell: On
Having been a PC guy since 1983, I made the jump to an iMac 27" at Christmas (new model) with 3tb fusion drive, 16gb memory and top i7 processor. LR works very well on it! BTW: my 3 catalogs are well over 200,000 photos in total.
The only thing else on the desk is a Thunderbolt Drobo stuffed with 5- 3tb 7200 rpm drives. As others have said, there are some limitations due to how apple provides its pc's for sale. I personally weighed them against my needs and took the plunge . Can honestly say I'm very pleased. Barring any failure and what that would mean (as others have already pointed out), I've protected myself via the drobo, a set of separate bare backup drives for all my photos etc... and a backup schedule. For me the one (and more expensive) issue will be the availability in the next 5 years of significantly improved pc's vs. today's and using apple, its a complete re-buy. That said, in the windows world, after five years the majority of the equipment will still have to be re-purchased. One could argue the reuse of certain equipment and in the end one is left with a pieced together system that most likely would not be optimal but that's a decision each person has to come to grips with.
Having been in the pc arena and built from scratch many of them of the years, I've come to the position that if I'm going to buy a new system it will be with the latest technology. Life in the electronics world is continuing to compress so what's new today gets replaced with something quicker than it used to. I no longer subscribe to coming in at "last year's" best deal. JMTC