Losing ShareBuilder was a heartbreak. There was no product as good, IMHO. The HN community suggested M1 Finance, though, which has been a pretty close alternative.
I've had really good interactions with ETrade phone support (working with them on employee stock plan related requests). It has been absolutely refreshingly good customer service -- they know their product so well and know exactly how to offer advice about how to use it.
I agree on ETrade, but the ShareBuilder product itsself was sunset after the merger with Capital One.
Their product was to specify a basket of stocks with percentages, specify a dollar amount, and then purchase on some cadence. Dollar cost averaging made simple. Before the various discount trading houses went zero-commission, this was impossible to do cost effectively, since you'd lose more in commissions than you'd gain from dollar-cost-averaging + diversification benefit.
Now with zero commissions, it is still hard to do because the process is manual. As an example, suppose you want to purchase $1000/wk of {NVDA 23%, MSFT 27%, GOOG 10%, TSLA 40%}. It should be easy to do. It was with ShareBuilder. You buy less of the stock as it goes up, more as it goes down -- the ultimate buy low "sell" high.
M1 Finance is the only product I found which does the Dollar Cost Averaging well with your choice of stocks. There are other products (e.g., Betterment, but then they stick you with stock portfolios -- better in theory, ahem)
