We stayed at Xandari for 4 nights in October and it was a fantastic experience. The grounds are maintained to a tee and the views are breathtaking. They have done such a great job restoring natural habitat to what was a coffee plantation, giving us a full taste of the exotic plants and vegetation of Costa Rica.
The property size is great. We spend a lot of time walking through the trails, looking at plants, flowers, waterfalls, vistas, etc. We didn't have time (or money for transportation!) to do any other tours or visit other Costa Rican locations, but we felt like we got a really good taste of the country just by walking Xandari's grounds. The entire property is gated and guarded 24/7. We took a taxi to town a few times and the cab checked in/out of the property, which made us feel very safe.
Changing topics, the hot tubs are amazing. We spent several hours each night at the Sunset Pool hot tub, enjoying drinks and looking out at the night lights of Alajuela. I can't rave enough about the staff. Everyone was very kind and helpful. We were taken to the resort from SJO by a hired car (arranged by Xandari) for a mere $20, which was extremely helpful. We happened to use a Groupon for this trip, which made it a great value for the top-notch experience we received.
The rooms are great. The terraces are spacious, private from the neighboring rooms, and overlook the valley and city. Everything was great!