Well , all things need to considered as a whole, sure the 9550 is a good steady performer, and if you ar not botherd about print speed then fine, go for it. It's the difference between £735 plus Vat and about £945 plus Vat - so in terms of money saved that is fair enough - however when looking at your time v money plan, it is worth considering. If you have a long queue of people , a quicker printer will help.
As for a second printer- well if you haven't got one already, then it would mean simply another dye sub, and no I haven't got anything other any cheaper than the 9550 to suggest ( it's just you mentioned a back up , and I was wondering what you meant , sorry.)
If you were considering the 9810, then it may be just as well to consder the new CPD70, which wil be about the same price.
And of course, there are other makes of printers out there......................