When you say slight angle, do you mean that the corner formed by the joint isnt a perfect 90, or that the joint itself is twisted? The first is usually caused by the fence not being square to the sled, the second the blade not being square.
Id reconsider not having a dedicated sled. I get what youre saying about not wanting a unitasker due to space restrictions, and im in the same boat. Thing is though, the sled doesnt have to be big, or take up a bunch of space, or even be made from the best materials. Mine is maybe 8x12ish and made from mdf. I can stow it pretty much wherever, it doesnt get in the way, cost me pennies to make since it was scraps i already had, and if i need to cut a joint, i just grab it and go. My last jig was a backer board i clamped to my other dedicated crosscut sled, and to cut a joint with it i had to first spend a half hour getting it clamped in the right spot. Every. Bloody. Time. And you know what? Bloody bastard never worked, the joints were always sloppy in comparison. Sure, its a unitasker, but its the best tool for the job.