I got mine in Christmas of 1988 and put it away in a box along with 33 games in 1991 when I had saved up enough to get a Genesis. I still remember making the decision to get it based on the screenshots from the hanging box art sheets Toys'r'Us used to sell the games back then. Years later, in 1997 I still had everything; I pulled it out one day after a stressful round of college courses, and found myself playing my old favorites most every day. Eventually I started buying games, going to thrift stores and actively collecting the USA library. I was having more fun with it versus the then current 32-bit games that cost $60 each. It was a no-brainer for me.
It was quite different collecting it versus now. Ebay was small, and it was still possible to find stock at thrift stores. I had to get the last few games going through other SMS collectors online. I noticed in the mid 2000's that every thrift store started pulling their game stuff to hold in store auctions, or online auctions. Most of the game stock I saw then was Playstation, the cartridge stock had exhausted itself. But at this time ALL used thrift store games dried up, and collectors moved on to buying cheap games from Funcoland and mom & pop used game stores. This was my experience anyhow.
Owning it back in the day felt like an exclusive club. Almost no one else had one, and I always felt the graphics and games were far superior over the NES when I finally saw SMB, excitebike, etc. The only places that rented games were a local Blockbuster and a grocery store. Remember when grocery stores actually operated their own video rental departments? I think that pretty much died in the early 90's.
I think the experience must have been like owning a Neo Geo in the early 90's and having hardware that was exponentially ahead of the competition.
Without owning the SMS, I would not be a current gamer now. It had a major positive impact on my life, for sure!