License system DRM Shareware or try and buy?

Hi, someone has implemented a system for manage license keys for shareware or try and buy games (for indies)?

i searched and find in internet:

www.siliconrealms.com/ Armadillo

www.licence-protector.com

www.interactive-studios.net/products/qlm.htm
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Indie developer friendly, this protect the exe, but i dont know if this affect performace:
www.ultraprotect.com/product.htm

Or the best way is to implement your own system, like microsoft shareware starter kit?