I haven't run a full bucket type car seat in mine, but I didn't get the Taco until after my son was big enough to use one of these:
Also got an inflatable booster so he could see a bit more out the window.
Harness is pretty well built and takes up very little room when not in use. It can be a bit fiddly to set up and adjust when you first get it, but after a while it's just as fast or faster to get in/out of that as it is a conventional car seat. It does lack some of the neck support that a conventional seat has, but there is an optional neck/head pad available. Forward facing only of course, but after you get past the age/size where rear facing is the thing to do, it's a solid option.