I see nobody has replied yet, so I'll start the ball rolling. I have an NXT 5 - photos here: Warning - it's LEFT-HANDED!
Pros: very very portable; looks great; extremely easy to play, as its action can be set as low as that on a bass guitar, and it's got DOTS! Adjustable bridge height makes bowing perfectly comfortable too; extremely easy to set up through holes in the back plate, without the need to remove the cover; has a fully adjustable tripod stand that eliminates the need to balance the bass on your body while you play - it stays where you put it and you can walk around it.
Cons: doesn't sound like a double bass, even with the corresponding switch activated; doesn't 'feel' like a double bass, and offers much less of a physical experience, because it's so small and thin you can almost play it like a bass guitar; the tripod is rather horrid to look at.
Er, that's it for the cons... I do like my NXT a lot; then again, a normal size double bass is bigger and heavier than me, and a lefty is practically impossible to find and try before buying/ordering one from scratch, so EUBs are just about my only option.