I've never kept erectus, but I love reidi. I think they are worth the wait. Give you a chance to set your system up.
I am inclined to try some erectus after my upcoming move, they are kinda cute. Barbouri and comes are also very appealing. Geesh, I like all seahorse species, I guess I'm no help.
IME keeping most species is just about the same. If you start with good stock of anything, the day to day keeping of the tanks is pretty much the same. I wouldn't set a tank up any differently for reidi or erectus, for kuda or barbs, etc. I do keep comes a couple degrees warmer, I would get a bigger tank for ingens. But pretty much all of the species basic needs are the same. It's when you get into raising fry, if you ever do that the challenges of reidi present themselves. Rotifers and breeding pods suck.
JME