eventer is a high quality allrounder i suppose.
Performance horse usually have a specific discipline. sports horse is a breed really..
Im sure otehr people disagree its a bit grey...
Lou x
to me i would take "allrounder" as nice riding club type whereas i would see "eventer" as BE standard.
"performance horse" would indicate has been bred to do a job (e.g. from great dressage lines) and "sports horse" for a competition type where they aren't sure how to desc breeding- e.g. my 4 year old is a regd. sports horse as he has a mix of warmblood, irish, TB etc so not a 'breed' as such
I would expect an allrounder to do fun-rides and hunt and be easy to hack, in traffic, etc, in addition to all the eventing phases which I would not necessarily expect of an eventer. I think the term allrounder implies a lack of talent to go on to higher level affiliated competition - so really agreeing with others.