I own and enjoy games from the 70's through present.
As others have said, all eras have their charms and strengths.
EM's have a completely different feel and nudging skills are paramount for many of these.
In the early SS era, engineers who had worked for decades with the more limited EM technology embraced the new technology and there was a kind of Renaissance explosion in design and imagination. Not all these ideas worked in the end, but this may be the most creative era for basic audacity of design of shots and PF.
In the alpha-numeric era into the DMD era (Whirlwind and until BW went under), the idea of a larger-scaled "story" of modes to accomplish and wizard modes to ultimately aim for came into being, so the narrative of games had a larger canvas to "paint" on. This resulted in a more integrated approach. Add ball saves to this, and you have an experience that emphasizes both the classic shots of the early SS era but with more depth.
Modern pins (generally WOZ and beyond) have been both more forgiving (ball save and potentially long ball times) and more brutal insofar as the player really needs to know the ruleset to be able to excel. This, to cater to the HUO and collector market. Players who will own games for years want something new to challenge them when they've played a game 3,000 times.
IMO, they're all good. It depends on my mood. Sometimes I really need a few games of EL Dorado EM and I laugh out loud if I get a house ball or manage to knock down all the targets and reset them. Other times, I'm loving the simple challenge of trying to rack up the bonuses in Fathom. The basic yet challenging aspects of Fish Tales keep me laughing or coming back for more. Another time, I might be in a mood to attempt to crack open a huge score in BM 66, trying to go through the main Villain modes, pick up Minor villains and crank the bonus multipliers in a 20 minute long game.
If you're talking about a collection, it depends on how much space you have. IMO, the fewer spaces you have, the less luxury you have to have older games. So few spaces = recent games. If you have the space and money, you're probably going to want a bit of everything for the sake of variety.