T.C.
She sounds completely normal. If your first was much easier than this, then I think you had an easy baby. What you are describing is how I would describe most of mine, only my first was WAY worse. She would wake up every 30 minutes to an hour.
My others never slept for long stretches beyond 3 hours. I think you're doing good to get such long hours in a row, even if it is only a few times. It really, really, really sounds completely normal to me. I don't think you are doing anything wrong or that there is something wrong with her. She's just being a normal baby.
My 4th has been my best sleeper. At 11 months she is starting to sleep for 8-9 hours at time. It's not most of the time, or anything, but it happens sort of often.
I don't do cry it out. I rock them to sleep as babies each time they wake up and won't go back to sleep. With my 4th, we've had to move her to another room because she is weird (hehe) and won't co-sleep very well! I didn't know babies like that existed. But she won't settle unless she has her own space. It took me a while to figure it out, but that is her preference.
When my hubby gets up for work, it always wakes her up. So she is now in her own room (the kids room). Often she will wake up and fuss for a minute or two. I used to jump and get her, but somehow I learned that if I leave her for a minute or two, she often settles back to sleep. Often she'll fuss for a minute. Stop. Then fuss again. Then stop. It might go on for 5-10 minutes, but she is not actively crying. It's more like she's fussing in her sleep. If she is actively crying and really upset, then I don't wait any time, and will grab her right away. But if she's only fussing, I will wait now, and she is often settled back to sleep in less than five minutes (and she is not crying that whole time. It's off and on fussing). With having so many kids, it's been a life saver to get more sleep to handle them and current pregnancy.
Anyway, doing it this way has led to longer periods of sleep for her. She'll often settle right back down. I never did it with my others because they slept in bed with me. I still sometimes try to bring her in bed with me when she wakes up, but she won't sleep. It's been so strange since I'm used to the opposite with my other three.
Rocking back to sleep is what I always do. I think it's a normal way to get the baby back to sleep, especially if you don't do cry-it-out.
Pretty much I see nothing wrong. It's totally normal. You aren't doing anything wrong. She's just being a normal baby.
The babysleepsite.com is a great website for ideas on how many naps a baby needs per age and how long at night, etc. It's really helped a lot.
I hope something in there helped. Good luck!