I agree with the others in that I'm sure it depends a lot on the situation. The age gap, your toddler's personality, outside help, whether you have a high needs or an easy baby, etc.
For us, it has so far been easier than I expected. (I say so far, because I am well aware that it may change.) Before we had DS2 I listened to all these horror stories about having two kids close in age, and how they would always be picking on eachother and I wouldn't be able to attend to both their needs. So, I expected it to be really, really, really tough. Mine are 23 months apart, and DS1 is now 2 1/2. DS2 is 7 months. While it has been incredibly hectic so far, it's managable. Yes, someone occasionally has to wait a bit, but I can usually attend to their needs quickly. But then, DS2 is a super easy-going baby who slept a lot in the beginning and still sleeps quite a bit during the day. Also, right now at least they tend to not nap at the same time, which is awful for me since I don't get a break, but good for them since they can maximise alone time with mommy.
The biggest change for me has been having few or no breaks in my day. Right now, DS2 is settling really well for the night, so I can relax after they're both in bed (around 8'ish), but at times that hasn't been the case. With one child you get used to relaxing a bit during naps or when they're playing quietly by themselves. With two, that can't be taken for granted.
Today, DH took care of DS1 while I took DS2 to the mall to do some clothes shopping for myself. He slept in the stroller for most of the time I was there, and I caught myself thinking how when I'm alone with just one of them it feels like a break, compared to the usual two.

Even pushing a single stroller instead of a double, felt like a breeze! So yes, it's more work, but to me being with both of them has become the new normal.