Fidelity's FNCMX vs OneQ

[PottedPlant]

We currently have $700K in Fidelity's FNCMX NASDAQ tracker. All is in a tIRA. The expense ratio is 0.3%.
I see that Fidelity's OneQ has an expense ratio of 0.21%.
What are the pros and cons of switching from FNCMX to OneQ?

[2pedals]

Probably very little difference in a tIRA other than the difference in expense ratios which is slightly better with the ETF. For me, it would become a personal preference to want to use a mutual or ETF (with a slightly better ER). In taxable I would definitely use the ETF.

https://www.portfoliovisualizer.com/bac ... ion2_2=100