I've messed with most of the common tools. (Haven't had a chance yet with the new Frankford Arsenal or K&M tools.)
The Hornady tool is a hand and finger killer, with a primer-flipping problem.
The Lyman is uncomfortable to use and made in China.
The Lee tools are junk, in my opinion; and that is only made worse by the need for special shell holders that have stupid-loose tolerances so they can work with more cartridges. ("Jack of all trades, master of none; so I specialize in flipping primers and seating sideways...") The Auto Prime is also a thumb killer.
My vote would go for:
RCBS
Universal Hand Prime
In my opinion, it is, by far, the best hand priming tool on the market.
I currently use the 'standard' RCBS Hand Prime, which requires shell holders. It works, and is far more ergonomic than most other brands.
But...:
Use the wrong shell holders, and it'll perform poorly. Lee shell holders, in particular, cause lots of problems (much like Lee shell holders in nearly any other application
).
The ram guides/inserts that slip inside the shell holder are a wear item and easily damaged with misuse. If you buy the tool, contact RCBS and ask for a spare set of each size/color (large/small ; black/white). My first set of "small" guides/inserts lasted about 2,500 primers before replacement. Subsequent sets and the large guides/inserts are all at 4k+ with no issues; but
will eventually require replacement again.
With certain brands/styles of shell holders, the ram guides also need to be slightly shaved/sanded to fit inside the shell holder. Hornady and Redding shell holders tend to work well. But some Forster and Lyman shell holders don't play nicely; and few Lee shell holders work without tweaking. (I swear I'm not trying to bash Lee here -- it's just my experience with the tools.)
And, as RCBS warns in the instructions, improperly changing shell holders can result in a misalignment of the tool's handle, lever, and plunger. It's not a huge deal, and is very easy to reassemble correctly. ...But fairly irritating if you're in the middle of changing shell holders - which requires two hands plus a couple extra fingers - and suddenly need two more hands to fix the misalignment because you got lazy and let the lever down too far.