Also, what games would you suggest to someone new to the platform?
It depends on which super-common games you already have. The Intellivision is a little different than most systems in that probably 90% of the games from its heyday are "very common" and probably 90% of its best games are among that group. I don't think of it as a system with a lot of hidden gems; its best games were generally its most popular. Some exceptions might be in the later INTV corp releases; mostly they just re-released older games but they did also put out some new ones and they were much more limited. I don't have a lot of those, although I do have a few of their arcade ports and sports games and they're generally good.
That said, obviously some games hold up today better than others. So here are some games that I think are still fun or unique, or are just best on Intellivision vs. other systems:
Bump n Jump
Tron: Solar Sailer
Tron: Deadly Discs
You'll need an Intellivoice for Tron: Solar Sailer and B-17 Bomber, but those are literally like $5.
Obviously that's not an exhaustive list, just games that I've played recently that I think are still fun. And they're all common so you shouldn't have trouble finding them.