Kelly, Baldwin, Shaver, and MVA are the choices. Shaver also makes an economy version of his sight, but the upper is made in the Ukrain and poorly rated for stability and repeatability. The Shaver high quality sight is the least expensive of the four choices, but comes with a Hadley eyecup that is top notch. The Baldwin and MVA are a bit more expensive -- each enjoying a strong following. The MVA is particularly well liked by serious competition shooters. At top dollar is the Kelly and it is a work of art!!!!
A globe sight with level is necessary for three hundred on out, so you'll want to look at Shaver and Kelly for those. Shaver makes a Lyman 17 size globe with built-in level, and also makes a larger diameter globe that takes proprietary apertures. The Kelly globes are large diameter.
A sad but true axiom when dealing with sights is: 'You get what you pay for' I've been saving for two years to get a set of MVA sights for my 38-55 Hi-Wall and a set of Kelly sights for my 45-70 BPCR. That'll be over a thousand dollars, all up for the two sets.
The trouble is, you can spend three hundred for mediocre sights and be very frustrated and unhappy, or you can spend 500 and be pleased. The good news is that quality vernier sights never loose value and can be resold. Lower quality sights are really junk and worthless at time of purchase.
Sorry to be the bearer of this news....