A bit of an overdue update:
Now that I've had said funds in Betterment for a while, I'm looking to move them out and manage them on my own. (Yes, I am sure to some of you the answer to this is "DUH!", but find it in yourself to step out of your experienced shoes and see if you can remember what it was like before you knew everything in the world. You can do it!)
I still have a lot to learn despite it having been a while since I started. But I want to note some of the reasoning for moving the funds out, some of which was not mentioned here and thus might be useful for someone else who's debating this.
The main motivation, I would say, is that I am still doubting my abilities to be quite the expert in financing as a lot of folks here (maybe that will change over time, who knows). At the same time, I want to feel like I want a certain level of understanding of what's going on with my funds. So...
1. Betterment's portfolio ends up being time-consuming to parse: there's something like 4-12 funds in the portfolio depending on the stock/bond slider setting, and even if the slider does not change, the fund choices and allocation could change over time.
2. Value-wise: thanks to explanations on this thread, I do not consider rebalancing to be worth the fee, so it really just comes down to TLH. As I understand it so far, there's a practical limit to how much you can tax loss harvest a given set of shares. After that, the Betterment fee is paying for a service with a diminished ability to get value out of. If I'm in a wealth building stage, there would be new shares that could be harvested, but even then it seems like over time the percentage of my portfolio subject to TLH seems like it would end up being the minority. Maybe there is some scheme to take money out of Betterment after it's been harvested and move that elsewhere, but that sounds like a major pain, at least more than the alternative of just managing less funds on my own.
3. Given the previous two points: to avoid a wash sale by an automated Betterment tax loss harvest, I have to track whether I have a fund outside of Betterment (including in IRAs, and more importantly 401ks which in my current and past jobs have overpriced funds except for one or two, those of which then happen to be ones in Betterment's portfolio).
Betterment's answer to this is to...move my IRAs to Betterment(!). Alternatively, you can link other accounts to them, but I never trust any site to keep my login and passwords to other sites, as it sounds like a security breach disaster time bomb (in some cases it's even against the T&C of the target sites to share the credentials).
In the end, my desire for simplification could be argued to be my own "fee" of sorts in terms of what extra money I might not make with a more complex, algorithmic management, but I feel like the merits of what that after-cost difference is (or if it value even exists or not depending on who you ask) could be (and is!) argued in these forums for eternity, but Betterment's fee is a given constant. (Side note 1: my desire for simplification may currently be confirmation-biased by
jlcollinsnh's stock series.) I don't feel comfortable that once my money is in an automated, sophisticated management system, I am practically giving up my ability to understand what is happening, which would increase over time. It gives me a sense that I must choose between understanding what is happening with my funds or blindly trusting what a third party would do. If I wanted to "check-in" on occasion, then I'm now putting in more time than if I just did it myself.
There are some other behavioral lessons learned for myself: Betterment won't prevent me from making a poor behavioral investment choice more than Vanguard. Both let me log in and see how my investments are doing and provide a metric to tell me how they are performing, so with both I will need to learn to surpass the desire to muck with my investments. (Side note 2: I'm going through
this great post about one's ability to handle volatility. I kept on course during the 2008 sad times, but that
drawdown, part 1 blog post really takes the perspective to the next level!)
Thanks again to @Dodge for the explanations on rebalancing, and to thew few others who took the high road to empathize with a newbie.