The best replacement for arduino mega is sainsmart.

The best alternatives to arduino mega are rated as following:
★★★★★  sainsmart
★★★★  beaglebone
★  ardupilot

Your alternative for arduino mega is not listed? Suggest!
Speaking about arduino mega, one probably shouldn't forget about ethernet shield.

Other search terms related to arduino mega and their ratings are:
★★★★★ ethernet shield
★★★ xbee
You have in mind a companion for arduino mega and it is not yet here? Propose!



Google Trends

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arduino mega
sainsmart
beaglebone