Completely agree, although my "customer service" veered off to hideous territory on several occasions. You'll also want to do a search here for IB and autoliquidation, variable and random margin changes...leading to autoliquidation, assessment of margin on futures debit spreads, and margin calculations that assume you can lose more than the max possible loss on a position...leading again to autoliquidation, among other known issues with them.I traded at IB for years (until 2016 - but never stocks).
I think I can sum up my collective experiences there in one sentence, really (which is actually pretty unusual, from a mouthy chick like me): my dealing costs were undoubtedly a little lower than they would have been anywhere else, but my customer service experiences were both very variable and overall probably a little worse than they would have been anywhere else.
If you only want to trade stocks in a Reg-T account they may be a good choice. If you need to trade Mongolian milk futures in the same account that you trade AAPL, they may also be your only choice. Other than that you're almost universally better off with someone like Robert if you're a mid-size trader or nearly any other broker if you're a smaller trader.
Sincerely,
Another unhappy (former) IB customer