Salvia is the only hallucinogen I've ever tried so I was unsure what the 'trip' would be. Trust me, when it hits, rest assured you will know beyond any shadow of a doubt that you are trippin.
5x, 10x, etc are concentrated versions of the same thing. If your new to the game, I would start with 1x and see if you want to kick it up a notch from there.
I've only ever used 1x but I have a nice long-neck glass bong with a huge-ass glass bowl that you can fill right up and I fill the neck with ice for a nice cool smoke since you need to torch the ever lovin' shit out of that bowl till the salvia is *glowing*.
Held that funky tasting smoke and sat back wondering.... well, now what. MOMENTS later I experienced what I like to call 'silly-putty' reality. Everything gets really stretchy and drawn out. Watching TV was like a pop-up book. Shit was off the screen and on the coffee table in front of me.
Have yet to try the 5x and up, but all the 1x trips I have taken are nice, intense, and over in 15-20 minutes. Very fun, everyone should try it.