Regarding Olivs, I haven't had them long but I understand they can last a couple of years. Slapping can shorten their life as I believe the principal risk is of the metal winding coming away from the gut. The nut and bridge also have to have appropriate sized slots so as not put pressure on the windings as you tune.
Regarding tuning, mine can easily shift a half tone overnight if the temperature changes. To my mind this is the biggest nuisance with these otherwise wonderful sounding/playing strings.
Lots of people seem to use Spirocore, Obligato or Evah E/A with Olivia D/G. I don't have a problem with the Oliv A so I use Oliv A/D/G with a Spiro Mittel E. If I did arco, I am guessing Evah E would be a better match.
There's. ton of threads on Olivs on TalkBass. Just search the strings forum. Here's the link:
http://www.talkbass.com/forum/f17/