Budget is not too high -at most £200 to £250 for the card for now(its just a starter until there is a budget) and it will be paired with a Xeon E3 1230 V3(Core i7 4770 basically).
I had a look through a few reviews of the professional cards,and it appears AMD has a lead for Maya and 3DS Max on the budget end,but loses to Nvidia for Blender:
http://www.cgchannel.com/2013/11/gro...nal-gpus-2013/
http://www.tomshardware.com/reviews/...card,3868.html
http://www.tomshardware.co.uk/best-w...-32728-19.html
I assume that the AMD W4100 should be better than the Quadro K620,unless they are some other suggestions.
What about the W5100 which is around £270?
OF course the other path is to use a consumer grade card - now would a GTX780 or R9 290 be better??
Would an R9 280 for under £150 be a good budget alternative??