My experience is that the type of compass you need is based on the type of navigation you expect to do, plus experience. Personally, I’ve never used the mirror-sighting type on an outing, although they are great for easily taking accurate bearings. On the other hand, I’ve used a conventional ship’s compass to take bearings, and triangulate position, routinely on sailboats – just sighting over the needle to the lighthouse or smokestack.
As for hiking, I’ve walked several thousand miles on the great web of trails in Europe, with only the tiniest of modern compasses. On my first trip, I needed no more than the little button compass that was embedded in my REI trekking poles. It decayed and froze up during the first month. (Incidentally, afterwards, REI told me it wasn’t intended for navigation – hmmn, I thought). Fortunately, I reached Limoges, France, just as that occurred, where I purchased a Recta Clipper compass. It’s sold as the Silva Clipper in the US.
For trail work, with occasional distant bearings, the odd cross-country “short cut”, etc. (with a topo map as Roger says), for 10 bucks and 5.9 grams, it’s pretty hard to beat. It’s been my http://www.longwalking.com compass of choice, still bubble free, for the past 6 years.
So it all just depends on the outing. Thanks, Roger.
Cheers! I hope to see you on the trail. SM