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For beginners AVR is not very recommended (Its just my suggestion) because mostly starters mistakenly program fuse bits wrong and this creates real frustration for them. PIC is very easy and have a lot of online support.
They have lots of differences and lots of similarities, but can get the job done. What you expect to do with an 8-bit microcontroller, you can do with both. So find out which one is more easily available in your area, cheaper, available in large quantities, etc. Pick that, learn that and master that.