Hi kivvi! I have been here three years now. I originally only wanted to stay for a year or two, but I actually love it here.
I speak basic German now. I didn't really speak it at all when I first came but I'd been doing Duolingo for six months and that was hugely helpful. I find I can make myself crudely understandable in almost any basic situation, I couldn't express my opinions on anything complicated, but I can talk to other mums at school/kindergarten and do shopping - including asking for help - and stuff like that. My German has of course improved since I've been living here.
DS was just less than 5 when we moved and he picked up the language within a year.
I found a meetup group locally for other English speakers and I joined that early on and it's been a lifesaver. Yes, it's probably slowed down my German acquisition, but these ladies are incredible. A true "expat family"!
Things I like are the freedom for children, I've grown to love the Autobahn, the public transport is phenomenal, the health system is hard to get used to, but generally excellent in terms of quality of care. German Doner kebabs are miles apart from the arse-and-eyelid offerings you get in the UK. I like all of the fests, you seem to have a fest for everything, so there's always something to do on a sunny weekend. Everyone gets silly around Oktoberfest which is amusing and everyone gets really festive for Christmas, which is wonderful. It's lovely to be able to just pop into the Christmas market on the way home from work/school/etc.
Things which I don't like is the shopping hours - just weird and wrong and takes up a huge chunk of Saturday doing food shopping because you can't just fit it in whenever, plus hardly any online grocery shopping (one supermarket offers it now, but with a limited selection plus it's more expensive and just not as good as Tesco delivery!) Hardly any Indian takeaways and the Chinese ones are mostly rubbish (or I suppose, just Germanised, really, like in the UK, the takeaways are all much the same as each other, but here they are very salty with not much flavour IMO. And from January to Easter it's a horrid dark cold slog with nothing to break it up, not even a measly half term break. I always say we should do a trip to the UK during this part of the year but we haven't managed it yet.
One thing to be aware of - the school system is okay. It's really not as amazing as people tend to make out. It's not terrible. But it's definitely not some kind of perfect magical school system that the whole world should emulate.
It is difficult to work if you don't speak German and you don't have a postgraduate qualification or specific training. I work as an English teacher which I actually have a qualification for, though apparently most language schools take anyone who is a native speaker. And I enjoy that a lot but contracted positions are really difficult to find these days and the freelance thing can be a gigantic headache when you don't speak German (which might be OK with your DH helping you.)
Feel free to ask anything else you want to know :)