All my trading money is at ib, all my conservative money is at Vanguard. I very rarely make a trade in my conservative account, maybe one or two per year, so commission is not a big deal. But expense ratios in my mutual funds and etf's is a really big deal over time. Vanguard Total Stock Market index is a low cost no brainer. Warren Buffet just won a million dollar 7 year bet by going all in in the Vanguard Total Stock Market index (about 5,000 USA stocks) and beating a hedge fund fund of funds for 7 years. But I could easily own the same investments at ib. Just like to keep trading and investing separate. The rules are pretty simple: It's ok to take profits from your trading account and add it to your conservative account. It's not ok and is forbidden to take money from your conservative account to cover losses in your trading account. If you need more money in your trading account, well, you need to get a job that pays you money. But once you send it to that conservative account, it can't be disturbed.
I have played with IB once upon the time...maybe 10-12 years ago...maybe I was confusing them with Timber Hill Europe AG
Same for me, although I have a couple of hundred bucks in etrade and tda accounts as well just to poke around on the platforms. Vanguard really is phenomenal, and IB isn't perfect for trading but it's pretty close.
I've had many brokers over the last 20 years, and for conservative money that I won't be trading much, I like Scottrade. The problem with most brokers is that they are constantly getting bought and sold. You sign up with one set of rules, and all of a sudden someone else owns your brokerage and starts changing everything around. Scottrade is a privately held company, so they have no investors to kow-tow to. They say they are not for sale, and given the number of years they have been in business, I suspect they mean what they say. They are definitely honest. You can call them on the phone and talk to a person without going through a crazymaking phone menu. They are slow at things, sometimes taking a couple of weeks to clear a deposit, but if you are tossing it in there for the next 5 years, that really should not matter. Their user interface is easy for the uninitiated to learn, and they will help you on the phone, politely. They are for investors, not traders, and they are no good if you want to do any fancy trading of any sort. Personally, for things I plan to hold for a long time, I use them if I am buying many (thousands) of shares and the $7 commission is therefore less than IB's 50 cents per round lot.
Final note from me - my wife's former partner who is now retired as a tax accountant (functioned also as) money manager uses thinkorswim platform and he is a life long ameritrade client. He is pretty savvy and quit his tax business because he prefers active trading. He is doing options. I am sure he too has both a conservative and active account.
Not knowing how much money you are talking about or your trading style ..... Just my opinion of course, but I am uncomfortable with IB's business model -- lots of active traders margined up (as demonstrated during Swiss currency crash, IB can absorb losses from that); you might not want to be in the same boat during a major market disruption -- and I use both Fidelity and TDAmeritrade/TOS. No, not the best commissions but they are big entities that should be able to ride out crashes better than brokerages filled with mostly active traders. Commissions at both of these companies can be negotiated down if your $ amount is large enough and/or, you are an active trader. Try for $4.95 flat for stocks at Fidelity (no futures there). It was harder for me to negotiate at TDAmer but then again, I don't have that much over there anymore. Trading platform and products/data feed available for trade at TDAmer/TOS much better than anything Fidelity has but you pay for that with the commissions. Fidelity commission-free ETF better (as of now anyway) in that you can scale in to a comm free ETF and sell out at any time within the 30-day hold period with only 1 commission charge as a "penalty" - a nice deal. Much less liberal restriction rules on the comm-free ETF's over at TDAmer, though they have more ETF's available.
FX is its own (rotten) bag of potatoes. If you own equities I'm not sure why you're concerned with a brokerage failing, and IB went pretty smoothly through 2008. If you have a huge pile of cash sitting in an uninsured brokerage cash account, well then that's just bad cash management in general. If you want to talk about black swan events the correlations generally go to 1 across the board. AMTD has 2.5bn in goodwill on their balance sheet for 2014, in addition to 3/4bn in other intangible assets (as compared to $0 in those categories for IB). It's really not fair to make pot shots at IB for the news article du jour (swiss franc) but omit massively glaring fundamental analysis questions. I'm not in anyway saying AMTD is ready to fold tomorrow, but I'm hard pressed to say it's more stable than IB.
I don't feel like my lone opinion on IB is a pot shot but more of expressing my sense of not wanting to be in the same boat with a lot of highly leveraged active traders if we have a REAL black swan market disruption. 2008 and on was not that. Yes, IB held up pretty well in 2008. But given the margin rate of 1.X% and the ability to trade so many futures products at such a good commission, IB is filled to the brim with big and active traders of those products. I was a client of IB's for a long time but have moved to more of a conservo mode. "As of December 31, 2012, Ameritrade had 5,836,000 funded customer accounts and client assets of $481 billion." Not sure what it is now but TD has a lot of stodgy money that is parked there and that soothes me. TD Amer also has FDIC insured cash sweeps accounts though they are moving the futures stuff over to another entity so that may change, I don't know. No offense intended to IB users, we probably won't have the type of black swan event that would knock IB out but I wouldn't want to have a lot of money parked there.