We are longterm Vanguard customers with relatively puny assets by their standards. We interact often with their site software. Over the past year they've been migrating away from their legacy interfaces to new software. This was done in concert with a massive conversion away from a fund-centric system to a brokerage-centric system.
The conversion has gone badly. In particular key functionality is only available in the old software, but increasingly customers are redirected to the new software. Which is missing key features.
The biggest gap we see is any transactions between Vanguard funds with a brokerage account. Many things that we used to do online now have to be done by phone. If you can get through their dysfunctional automated phone tree. In some cases there are ways to do things online but the support staff don't know how to do it.
Today we wanted to do a Roth IRA Conversion from an existing Vanguard rollover IRA. The software no longer supports that! It does support moving money from Fidelity though. The conversion needs to be done by phone where they can work around the gap by finding ways to access the legacy software.
Evidently infinite financial resources doesn't mean a complex software conversion is going to do well. If you're not a Vanguard customer you may wish to consider Fidelity instead.