From experience, it is a tougher division, but it isn't La Liga. Though I would love to see Messi at The Amex. (For five minute before his first hat trick at least!) We yoyo'd a bit previous to this stint but that was when we weren't really set up for this league. If/when you get promoted I'd be surprised if you drop back down in the first season. Last time we came up without
massive investment we finished 10th.
Now, I think it's getting a little harder/more expensive each year to compete, but by being frugal and signing the right players (Not those big name wage packet players) you'll find yourselves competitive. Finding a reliable striker in the Championship can be difficult, as the step up can prove difficult with defences being much tighter, it's an instinctive thing, strikers just don't get that half-second to set their feet or adjust balance in the Championship most of the time. Though I'm in no way dissing you're current squad or suggesting L1 is a cakewalk, far from it.
I must be honest I know very little about your scouting and recruitment, but you must be doing something right to be where you are.
There's always going to be team (especially those on parachute payments) throwing silly money at players but as the likes of Derby, Villa and to a lesser degree Wednesday are finding out, spunking stupid money doesn't guarantee promotion.
As a solid, well organised unit you'll be fine, add a couple of faces in the summer and it'll no doubt be an exciting season ahead for you. With that said, you still have to get there, so it's maybe best to not count your chickens as they say and enjoy the ride; best of luck, in my own little way I'm rooting for you.