Luang Prabang or Siem Reap
 

Because of the vagaries of air flights, I have a choice of spending 5 full days in Siem Reap/ 4 full days Luang Prabang or the reverse 4 days SR and 5 days LP.
Based on your experiences, which would you recommend. I am a very outdoors person, enjoying hikes/treks, etc.
I also enjoy soaking up local culture/history and am a believer of of the slow travel principle. I am staying in locally owned hotels/guesthouses while in each place.

P.S. Thanks to all who are posting their trip reports. I am enjoying them and gleaning ideas from them.

If you at all interested in the temples at Angkor, I'd spend the longer time in Siem Reap. There are dozens of acccessible temples, and there is no way you will see all of them. We spent a week there and could have spent more time. We also loved LP. It's more of a soaking up the atmosphere kind of place.

As Kathie said, it all depends on your interests. If you love temples and/or archeology spend the longer time in Siem reap.

I think there's more to keep you busy in SR, so I'd spend more time there.

Based on your preference for outdoors experiences (hiking, trekking), I would look into spending more time in Luang Prabang and environs. Laos is a beautiful country. We only had 3 days there but if we had had more time, we definitely would have spent it outside LP exploring the countryside.

The temple area around Siem Reap is vast and could keep you busy for many days but I didn't find it particularly attractive. There is also the danger of stepping on a land mine if you are away from the main roads and attractions.

Just reread your post and based on your interests I would spend the longer time in Luang Prabang.

LP. The temples around SR are a unique experience, but a complete tourist experience. In LP, you can quickly get outside town into the countryside. I would skip the caves and take a boat up the river to some villages. We were the only westerners in each of the villages we visited. While there was clear commerce designed for westerners, it was refreshing not to be amongst a gaggle.

My vote is for LP too....The Temples in Siem Reap are awesome, but the terrain a bit dismal....LP does not offer the archeological "Wow" but is beautiful.....