Fb550 & fb750
FB's are solid printers but they are outdated, there are many better technologies at the moment printing better and faster.
I think you need to re-read the original post - how can the printers involved be outdated when they are so new they haven't been released yet!
Seriously though in essence the FB range to date is a reliable cost-efficient UV printer for the Signage market - it has a very small footprint, excellent ink adhesion and is very easy to maintain and use.
To date the IQ has not been able to match an Arizona etc for very high quality photo-type work but it's not designed for that.
Similarly it has a belt rather than a fixed bed and so is designed for sheets and rolls rather than objects like a fixed bed machine can handle.
It doesn't have LED light so it runs a little warmer than LED bulbs so you might find very thin card or thin plastic might bend a little more - but it has two rollers to hold things flat as well as a vacuum so it rarely causes issues.
If you print large sheets 4x8 etc then the FB has no speed benefits over a fixed bed machine but with small cut sheets it is much quicker in terms of workflow - all the taping and loading / removing you need to do on a fixed bed machine with multiple small sheets makes the FB a better prospect for this.
Finally it is an HP - full of clever technology and a huge support network. There are plenty of alternatives but many choose HP for chiefly this reason.
The FB has sold in its thousands and is a reliable and proven workhorse.
I don't know the CET personally - it may be a great printer but would I want to take the risk with my hard-earned money on a company & product that may not be around to support me in 3-5 years time?
So there are a lot of things that make the current FB a great choice even if it may not be as quick or IQ as high as other offerings.
Now to get to the point - the new FB550 and 750 have addressed both these areas - the IQ has improved (I've seen samples and can attest to this) and the speed has increased by about 20% from what I can see.
Thus the new FB range upgrades make it a serious contender with other current alternatives.