I built one before buying real pins and it was nice to play a lot of machines but it's definitely not the same as the real thing. Also, even though there are a lot of machines available for you to play a lot of them are not all that great (but usually are being worked on). Pretty much anything by jpsalas is great but the quality of tables sometimes leaves much to be desired. I actually found a lot of the older machines "translated" better to being virtualized. Now that I have a handful of machines I don't play the virtual anymore. I do play the pinball arcade on my table quite a bit though so I might suggest that route as well.

I built a small (3/4 size) table using some old montiors 27"/19" and ended up getting a 37" TV and building a bigger one and while a bigger one is better I actually kind of like the idea of the tabletop virtual pin if you're going to build one. I think I might actually go back to that just to keep the machine alive. The small one was still pretty fun for what it was.

So maybe build a small one and get a real machine.