Kinda Depends on what you want/like.
I built a dedicated virtual pinball cab with 3 screens a while back and it is all fun and nice. I don't think I'd want a cabinet that is dual purpose. But, that is me.
As for an arcade machine, some people really like the authentic CRT displays. I've been playing with the idea of making a "virtual cab" and I was fortunate enough to get a good deal on a cheapo 4k TV, so I'm going to begin working on that pretty soon (I keep getting caught up working on bezel artwork ). The advantage to me is that I can use the bezel artwork to simulate the cabinet and not just the screen. With the newer versions of MAME supporting HLSL you can make the actual game "screen" look as good or bad as you want. Meaning you can get a pretty decent simulation of a CRT on your flat screen monitor. Additionally, the Vector games look pretty decent with 4k resolutions, but they still fall a short of the real thing.
That having been said, I'd suggest trying it out and see what you think. For me it was a no brainer to get flat screen. If I REALLY want an authentic experience, I'll buy the game or roll down to my local retro-arcade.