There's a lot to be said for either arrangement. If you have a partner who keeps different sleeping hours, the front bath does a great job of creating more isolated bedroom space. A downside, however, is the air circulation into the loft isn't great. Some people have found this to be a problem and have added fans to move the air from back to front.
The side-bath plan does not have a separate, private space, but it does have a much more roomy feel to it. That can be really nice when you're stuck inside on a rainy day. (But then so can separate rooms, I guess.)
Another thing to consider is how comfortable you are in the 6' x (less than) 5' loft bedspace of the Scamp
. The 6' tall prior owner of our side-bath 5er found he could only sleep diagonally in the loft, so he either slept alone up their or brought the (slightly wider) dinette berth down and slept there. Lynne and I also found the loft bed cramped, and have completely re-designed the loft end of our trailer
so the bed runs front-to-back over what used to be the gaucho sofa/bunk area. We couldn't have done that if we had a front bath Scamp.