1. The Unicorn Magnum is a great mill if capacity and output are your top priorities. It also handles large peppercorns better than most due to its huge mechanism. However, it is unattractive and takes a lot more effort to turn than others.
2. If you are unhappy with your existing mills, try cleaning it. The easy way is to replace the peppercorns (discard if soft or damp) and replace it with uncooked white rice. Grind away until you no longer see black specks coming out the bottom and then replace the rice with peppercorns. Assuming the mill was a decent one in the first place, it should be like new. There are plenty of junk mills out there so be prepared to be disappointed. Better peppercorns (larger and/or with more essential oils) tend to plug a mill much more quickly. Some mills tolerate this better than others, but consider it a cost of being able to grind the good stuff.
3. If you can afford it, I suggested buying quality. I meet people all the time who still have a mill they received as a gift or purchased, 20, 30 or even 40+ years ago. There are likely to be very few things that you will keep and use as long as a good mill.
4. If you think "crushing" peppercorns is in any way better, then you probably think PT Barnum never told a lie in his life. In any case, milling almost by definition involves crushing and grinding. This is not a feature, it is disingenuous marketing.
5. Ceramic mechanisms are not necessarily better. It simply allows mfrs to use a single mechanism for both salt and pepper. Product specific grinding mechanisms are almost always better.
6. Peugeot invented the pepper mill and still makes one of the better ones. The downside its that it does not grind as coarse as some other mills. This may be because Europeans generally prefer white pepper and prefer it ground fine. I suspect other European mills may share this limitation. I would guess that 75% of the people i talk to prefer coarse (or cracked) black pepper, so this is worth checking.
7. Avoid acrylic Mills. They are expensive and brittle and do not retain its shiny good looks very long. You will drive yourself nuts if you try to keep them "like new" clean,
8. Never buy a mill already loaded with pepper, or its cousin, the pepper container with a built in grinder. "Throwaway" does not even begin to describe these products. You deserve better.
9. If you are spending more than about $40-50, you are either paying for extreme size or nicer aesthetics. Neither one is bad, but good mass produced mills are available for very reasonable prices. Some even offer a lifetime warranty. It is also not hard to to find one made in the USA.
10. Size matters. If you want cheap and ugly go small so they take up less space and are less visible. If you want a classy commercial or handcrafted mill, 10" is a good size. It is big enough to do some interesting things design-wise, and it is still small enough to use comfortably while seated at the table. For custom builders like myself this is the most popular size by far. If you are a server or simply want something larger, 14" is also a nice size. Anything much larger will lack proportion and style, and the largest ones are simply ridiculous looking, heavy and hard to use.
11. On the subject of style, everyone has different tastes, but do you really want a mill with as many colors as a jockey's silk jersey? Or do you really want a pepper mill that looks like a baseball bat or a wine bottle? Why do people do this? Do you see wine bottle makers trying to mold glass to look like a pepper mill? A handcrafted exotic wood mill can be "jewelry for your dining table". Consider shopping accordingly.
12. Electric Mills have become more common. I own them, I use them and I sell them, but they are my backups that I use when one hand is holding a plate. I hate having more things that require batteries and all of the electrics are made in China, if that is something that matters to you. I suggest not making an electric your first or only choice.
13. So if acrylic is out, what material should you buy? There is stainless steel; it is economical, easy to clean, will keep its looks, and is easy to clean. There are stained and lacquered woods. These are nice but wear from use will eventually show and it may bother you. A light or natural color wood finish can make this less noticeable. There are also some painted woods mills that are colorful and whimsical in design. Not my cup of tea, but many people love them and you might even get an original design signed by the artist. I like wood. No, I take that back, I LOVE wood. I like figured, colorful exotic woods. With the natural grain and color showing, nothing is more beautiful. It is warm to the touch, silky smooth, and a luxury to use. Even domestic hardwoods can be affordable and every city or crafts fair will have an artisan with nice products to choose from.