Strengths: Low cost, easy to use, sufficiently accurate for purpose
Weaknesses: Not as large a base as some others
Overall: A fantastic piece of kit that everyone should have. Realistically most of us aren't going to need the random other features compasses seem to have - with just this basic model and a knowledge of navigation you should ba able to navigate with exceptional accuracy.
Far better to buy this low cost model and spend the money saved on a book teaching how to use it properly than waste money on more expensive and often more cumbersome models.
Having said that be sure to buy a Silva - cheaper brands just aren't as reliable or durable when you need them to be.
Strengths: Normally it's all you need in a compass - clear, simple, accurate - but...
Weaknesses: I got mine out in a near white-out on a featureless Glyders plateau and blow me if it didn't point South. I spent half an hour checking and rechecking my bearing and eventually convinced myself to trust my intuition and not the compass.
Overall: I emailed support on the Silva website and almost immediately got a really helpful reply. Yes, it is possible for a compass to switch polarity, for instance if you get it too near the magnets in a car speaker. And it's possible to switch it back with careful manipulation using a magnet. So nothing wrong with the compass - just be careful where you leave it.
Strengths: ease or use rock solid reliability reasonable price only 30grams
Weaknesses: measurements in metric only
Overall: ive had mine for many years, its been dropped, squashed, battered and froze. its simply never let me down, even when my navigation skills have!
if you get one of these youll never buy another compass!