Please tell me about Non-Ardurino "Brand" Ardurino board products?

I am a completely new to Arduino and looking to purchase an Uno R3 board. I am seeing Arduino and Sunfounder "Brands". is the hardware open source too? Can I count on the compatibility of these non-Arduino brand products? Thank you in advance for your explanation and reply.

This might help.....

Thank you,
It seems SunFounder is not contributing to the project in anyway. I have an Arduino board I purchased at RadioShack that I have not opened and was thinking of returning in favor of a sunfounder kit that includes some nice things. I will keep my board and look for alternative pricing on the "nice things".

I would like to suggest that Arduino put up a "Make a Donation" link so that people could feel Ok about getting better pricing on compatible (Not Certified) hardware and still make a small donation to support this effort. I have seen questions in the forum where people mentioned they are using the Sunfounder UNO kits. Maybe we could all mention to these people that donating a small amount of the money they saved would be a nice gesture since they are coming back to the community for help.

Just a thought. Time to shop for my other nice stuff :slight_smile: