Some things to consider before buying a rear kitchen model.
The rear of any trailer takes the biggest bounce when traveling.
More weight at the very end of the trailer, versus centered over the axle, will affect the handling and stress the frame more.
If the refrigerator was installed in a slide, it may be shorter than one installed elsewhere. Also, a refrigerator in a slide will have less cooling so fans might be installed, reducing battery life. Side vents may interfere with a slide topper if you want one.