I had the rx75. Gave it to a friend on the weekend. It's a good unit, solid performer. However, I have preference which I would go for before it now.
Hohm slice use code SLICEPRICE is half price. It's single 26650, I found single 18650 is just not the juice. This is what I use as my single battery portable now.
If you need more information ask. No experience with the presa.