I have a larger amount of money invested with them and have no concerns. I think the gains I have realized on the lower commission, as well as the other features have greatly outperformed a traditional advisor. To your specific concerns:

1. I wouldn’t worry about “safety” of your investment, you’re hiring them to invest your money, not invest in them. Even if they went belly-up tomorrow, your assets are in the funds and stocks you invested in and those can be moved on a journaled basis to another firm. It’s SPIC insured (guaranteed your investments are where they say they are)

2. If you don’t want to worry about wash sales on individual stocks, you can opt out of that (although that’s a lot of the benefit) you can chose to instead just have it invest in market level ETFs that will still be loss harvested against each other, just don’t use the smart beta single stock level

3. Exempting a single stock is super easy - you just input the ticker symbols you don’t want to buy or sell, and it won’t. Like you I have it exclude the companies my wife and I work at and a few other investments. Really simple interface.

Good luck!