I did the Vitoria race two years back when it was still independent. Lovely - not sure how much has changed with the IM taking it over, but in a nutshell:
- swim in a lake out of town - water great, was mass start with plenty of fighting for the first 400m. Spaniards do not take prisoners. Australian exit for second lap.
- bike - from memory it was something like 1000m vertical, so not too bad. loads of long shallow descents to keep the pace up, there is one long draggy climb that you do twice, one shorter climb you do twice, and one 12% climb that you do only once on last half-leg - that one was a real lung buster
- run is all in central vittoria, fair bit of shade but all on concrete
overall, superb surrounding and support, i had a great time. organisation could have been better (bit random with bike check in, their checklist did not include all the things you actually had to bring on the day), swim start is out of town with taxi or bus the only reliable way to get there. IM will surely step in organisational aspects behind it.
Plus, Basque cuisine is fantastic, the whole area is super green and there is plenty of sightseeing/things to do with family around… Do it!