Seeing as the Mac Pro is still 3 years old and an update is within 12 months, I don't think consumers should buy now,
I think the problem is that the "Buy Now"/"Don't Buy" tags overstate the issue and sound like judgements on the suitability of the product.
What they're really used to mean is just "Updates coming soon" or "Recently updated".
In the case of the Mac Pro, the unspun truth of this week's announcement is that the Mac Pro
isn't going to be updated for
at least 9 months, realistically 12 months and, quite possibly, possibly even longer... and
that's assuming that the new MP is somehow a direct replacement for the current model. So its "safe" to buy in total confidence that its not going to be superseded in the next few months.
If you're running the sort of pro software that can really take advantage of more than 4 cores, dual OpenCL-optimised GPUs and have a heavy enough workload to need the extra stability of ECC, and
haven't already switched to boring-but-functional workstation towers from Dell or HP, then this is one heck of a price cut and you probably should buy now. Both of you. (if not, the top end iMac will smoke the nMP on "mixed load" computing, costs less and comes with a free 5k display...)
Seriously, we're probably talking about customers who have already bought into the Mac Pro cylinder concept and need to replace failed machines or add extra seats to their existing ecosystem.
The other factor - AFAIK a lot of commercial outfits get their equipment on a 3-year lease. The early nMP adopters will have leased their MPs about 3 years ago. I wonder why Apple might be panicking just now...?