Having used both old (round tray) and the new, XR (square tray), I had no real problem with either ... following the usual learning curves for each. What I didn't like about the old style was that the nubs holding the cover would wear with age and the cover would NOT stay on if you had to put the unit down. As for the XR, yes, the ORIGINAL cover tabs were weak ... though I loaded several thousand cases before they finally gave out. The NEW design covers seem to have corrected this weakness ... we'll see.
That said, I've always had good service and a good relationship with Lee ... Mary on the phone and Dave Shano (sp) on the tech side. Just remember, work with the tool (whatever tool, as a general rule) and learn how "it" wants to do the job ... then adapt to it. If you do that, you're a team and not fighting each other. For me, after loading primers and locking the cover, I hold the tool straight up and angled away from me about 45 degrees. When I need to reload the right side feed way, I bring it back straight up, roll it off to the right to position the primers, bring it back up and then angle to 45 degrees again and the off to the races. I can prime 50 cases in somewhere between 5-7 minutes without straining ... and that's more than good enough for me.