I began working with AVR's as a hobby about 2008, before that it was all computers. In 2011 I accidentally stumbled across the Parallax Propeller P8X32A and began using it as well, it being the second MCU that I did play in, then the world between worlds came to light with the release of the Raspberry Pi in 2012, as much MCU board as SBC, both computer and MCU, and I continue to play with all three, and they are all great setups.
Though had I found Arduino before finding the P8X32A I would likely have settled in to Arduino, with a little raw AVR on the side and still probably added the Raspberry Pi. Though the Arduino would likely have been my primary board for MCU applications for a long time had I looked into it sooner.
The Arduino HW simplifies life a lot, and the software is so well thought out, the two together make developing new applications (HW + SW) very simple.
So I am glad to get into the Arduino.