What's your experience with lithium?

I was on 900 mg lithium (in addition to other meds) for about 8 years. It worked very well for me. Until it slowly decreased in efficacy, then stopped working entirely.
I had trouble adjusting to it at first. It caused horrible GI problems the first week. It also messed up my balance. The first two weeks, i was walking around like a drunken sailor. This improved and i eventually regained my sense of balance well enough that i appeared to walk normally. However, i would just randomly lose my balance sometimes and i remember a lot of scraped knees. The balance problems it caused always were obvious to my neurologist when he did basic tests on me.
Lithium, when combined with depakote, also made me have horrible tremors. My handwriting was atrocious because any attempt to hold my hands steady for any length of time would cause the tremors to begin.
I never had a balance issue before lithium and my balance problems vanished once i stopped taking it. The tremors improved significantly once i discontinued depakote. I can take just lithium orjust depakote w/o having tremors. They really only occur when i am on both drugs.
I also suffered from hypothyroidism while on lithium so i had to take 50 mcg of levothyroxine as well. I never gained weight bcs of the hypothyroidism. The only symptom i had was hair loss. My dr checked my thyroid in a routine blood test and it showed up then. Now that i am not on lithium, my thyroid is completely fine.
Lithium stabilized my mood well for a long time. I am bipolar 1/psychotic features. I needed an antipsychotic in addition to lithium as it did not prevent me from having intermittent psychotic episodes.
I honestly wish it had not stopped working. I was put on it after various psychiatrists tried just about every other option and none of them worked.
I stopped taking it after an epic & disastrous mixed episode in which i was "acutely psychotic" (as per the psych ward psychiatrist). I was taking that, plus a bunch of other meds 2 years ago, and ended up hauled off to the psych ward by the port authority police because, quite simply put, Terminal 1 at JFK airport IS NOT a good place to be psychotic. . .
It is rare for lithium to stop working completely, but it does happen. It happened to me.

@goaskmyalias, I'm so sorry lithium stopped working for you. I've heard and read of drugs that just out of the blue, stop working for a person. So sorry to hear this happened to you.

Perhaps the lithium is very good for bipolar 1 and very awful for bipolar 2 because placate the mania but for a mostly depressed like bipolar 2 increased the depression?