Not built or flown either and of course it depends on what you want; apples or pears.
Try buying a newly finished Europa. Not that difficult, in fact a fair few seem to come up for sale upon completion.
Now try to do the same with a newly finished RV.
A quick look at G-INFO reveals:
RV registered: 110 current permit: 58
Europa registered: 188 current permit: 126
The AAIB reports for the Europa (33) mention loss of control in the take off or landing phase 13 times (all relating to the monowheeltype) and a problem with the retractable monowheel 8 times. Both these problems have been addressed by modifications. The rest was a variety of mechanical and piloting matters (nosegear collapse; fuel contamination etc)
For the RVs I could only find 3 reports on the AAIB site. One related to a probable powerloss; one nosewheel failure and one whereby the nosewheel got bogged in on landing.
In the end factors that need to be taken into consideration when deciding what to get should include; mission profile (?aerobatics); price ( I think not a lot of difference there); operating costs (Europa more nimble dont know about insurance); seat configuration (SBS or tandem); preferred material to work with; hangarage/storage (no detachable wing option with the RV machines); and what does the heart say (beauty being in the eye of the beholder.
If you are going to build either, make sure you use appropriate protection. More people end up in Accident and Emergency departments as a result of DIY than any other single cause. Further for working with Epoxy use appropriate gloves as a lot of people do get allergic to the stuff and when using with rivets (the blind not the pop variety) wear earprotection.
No doubt you have already looked here:
For Europa Aircraft
and here:
For VANS RVs
HTH
FD
Declaration of interests: none