O/U's are more forgiving on reloads - if something isn't sized or resized quite right..or bad crimps, etc....
Last I knew MEC had 90% of the market...and I like MEC. The machine I'd recommend on a budget is their Grabber model. The Grabber does not auto index, so you have to rotate the shell holder after each cycle of the handle...but it has a good resizer ...and does a good job. Its probably capable of about 4 - 5 boxes an hour.../ its a progressive --- but its really easy to use. I wouldn't go with a single stage...some of the cheaper ones do not resize ...and it just takes the fun out of it ...when you are shooting 6 boxes a week.
The next model up is the 9000 GN ...it auto indexes ..good solid machine ...probably 10 boxes an hour. The top of the line machine is the hydraulic 9000 HN ...and its faster, gives you a nice consistent shell...but unless you're really going to be a competition shooter...you don't need the hydraulic. But if you go hydraulic - you only need one pump and one motor ...and then you buy the 4 loaders in each gague ( 12, 20, 28 and .410 ) ....and just swap out the loaders as needed...on my hydraulic, I have a manifold on top of pump - so I have 2 loaders on my bench all the time / 12 ga stays there all the time...and the 20ga, 28ga and .410 rotate in and out. ( pump and motor stay on floor - press is actuated with a foot pedal).
They do have an electric option - where loader sets on the elec base that actuates the press...but I'm not a big fan of that option.
Check out the prices with Recob Target Shop online ...they are good folks, and good prices. http://www.recobstargetshop.com/index.htm
If you stay with MEC --- its easy to get parts if you need them / lots of guys have them so they can help you on setup or crimp issues adjustments...and if you take care of it, you'll sell it 20 or 30 yrs from now after you've loaded thousands of shells for way more than you paid for it.