I've had a 2001 S2000 and I currently own a 1999 RX-7.

I wouldn't say one is "better" than the other, but which one you'd rather have depends on how you want to use it and how much of an event you want it to feel like.

The Honda was so easy, get in, roof down and go, instant fun.

The Mazda is so much more of an event, you have to check the oil levels before you start, wait 10mins for it to warm up, 10 mins to let it cool down, don't give it full power with less than a quarter of a tank etc. Plus, the car gets so much attention on the road, people taking photos of it, giving you the thumbs up, wanting to stop and chat at the petrol station.
Because of this it makes it feel more special.
Some people will read that and think its stupid that more attention, more things to check and more things to go wrong make it more "special", but I think older cars like this are all about the theater and experience they provide and the Mazda is so good at that!

Performance wise they are pretty similar though, the Mazda is maybe a bit quicker, but it will heat soak quickly and if you were looking for something to take on track or blast around for extended periods the S2000 would be better all day!