Well, depending against who you are playing, it's actually much harder than offline. The AI isn't programmed to attack you except if your creature gets in it's influence, and it only attacks your creature, not your villages or anything else at all. Playing online however, your enemy can do exactly what you can do, so I find it way more interresting. There are only 5 things that I don't really like about online mode, but they are just small things:
1. The villages you own have a belief cap, meaning you can't get more than a certain number of belief stored in a village, which prevents big wonders from being built except with an artifact (usually it's 500 for most villages and 1000 for your starting village).
2. The creature help, things saying like "your creature is hungry, feed him" at the bottom of the screen, cannot be activated online.
3. The in-game chat function is not really efficient.
4. This is only true now and was not then, but it's a little hard to setup to be able to play online, let alone to host a game online. I'm having issues at the moment for hosting, but I can join someone's game online though.
5. You can't save an online game.
Apart from that, personally, I love the experience online. Since your enemy(ies) can do just like you can do, you must always be on your guard, or you can even play in co-op two players in one temple with one creature. Creatures also are finally legit since they can die from hunger and fatigue (the AI's creature stays alive forever) and are way more interresting since they belong and were trained by real people. However, since you cannot save an online game, you always have to play fast if you want to get somewhere, and if like me you like to take your time building and taking care of your villages and creature, it can sometimes feel a little rushed.
In the end, it's pretty much just a different feel of the game. Not better or worse than offline, just different and interresting
P.S.: I'm taking this moment to inform anyone interrested in playing online with me on King Warg's client that I have upgraded to 1.30, in case someone with a P-5 glove ever pops up and wants to play online. Though unlikely, we can't be sure it won't happen someday. Good day