I'm so new to riding that this opinion probably isn't worth the pixels that are used to display it, but I *have* spent a lot of time wearing tall form-fitting boots (for fashion purposes). From that standpoint, the half-chap + paddock boot does feel *very* much like wearing a well-fitting snug pair of boots. The half chaps hit right at the knee and I get a lot of feedback from the top of the chaps about the position and angle of my knees. Ditto for the ankle, but there most of the action is from the paddock boots themselves.
Also, I do not know if this is standard for half-chaps, but mine have this interesting stretchy rubbery substance along the inner leg. Definitely some of the function of that is to make the half-chap stretch and fit tightly, but it also seems to have a similar effect as the leather (or whatever that stuff is) patch that is on the inside side of my breeches.
I would like to try tall boots sometime, but my feet are hard to fit even with normal boots, and I am pretty sure that if I can get the tall riding boots, it's going to be a custom job or special order...so I figure I will wait until I think I want to show before I mess around with those.
I usually change into my paddock boots and put on the half-chaps when I get to the stable. If it's actually on my body I don't have to keep track of it. :) The combo is plenty comfortable for grooming, cleaning, all that good stuff.