TSP Expense ratios for all funds are .038% and a couple are at .039%.

Our DPSP Offers an S&P 500 Index fund at .01% a Small & Mid Cap Index fund at .03% and a Bond Index at .02%.

Life cycles funds are .06% and actively managed funds have expense ratios anywhere between .29% to .93%

There is a quarterly maximum administrative fee on the plan of $4.25, so $17 annually. It can't go higher than that unless it is changed in the contract with fidelity. However, this is a maximum and I've never seen a $4.25 quarterly fee. Mine tend to be $1 here, $0.11 there, etc.

For me, having everything in one place is worth it, especially since we have lower cost alternatives depending on what you're looking for. Also, you can roll your TSP into a Fidelity Brokerage Link account which allows you to use your Delta contributions or your TSP Roll over contributions to buy lower cost ETFs such as Vanguard ETFs. The cost is $4.95 to execute these trades and many of the vanguard ETFs have similar expense ratios to that of TSP funds.

I think the article has validity in that these companies will sell you into a specific fund which will have a higher expense ratio. If you can get your money into the DPSP and not let them dictate where you should put the money and do your own research I think you can come out on par with TSP if not better.