I've been trimming my own hair for years now - just a standard fade, its not hard at all. I also cut my dads hair.
I have gone through ALOT of different clippers. The only brand that has stood the test of time and stayed sharp is Wahl USA.
I've had the Wahl for about 4 years now and it has never gone blunt. They are good for cutting, trimming and shaping...And it can take a beating from thicker, coarse afro and similar hair.
http://www.wahl-store.com/
But I have an old school Wahl that doesn't look like anything on the site....But i'm sure newer models inherit the same quality.