Bigger pots will never hurt you. Smaller ones can create some limitations. So all else being equal and budget not a concern, go big. That's not reality tho.
If you have a full 8 feet high to grow in, I say go bigger. If you are say in a 6.5 foot tent, the smaller pots will not be a problem because you will have to flip sooner to keep your plants out of the lights.
If you have control over the growspace (temp, rh, ppfd, etc) then I'd recommend bigger. If not, save the money, grow smaller plants and use the extra money to get the systems in place to control the grow.
I'm speaking in generalizations of course, I really know nothing about what you are trying to do or your skills / budget.
There are important tools for RDWC like PH meter, TDS meter, res temp meter, and for sure RH meter controlling a dehumidifier. RDWC can cause explosive growth resulting in very high RH. If you have to choose between 5 gal and 10 gal, and with the 10 gal you can't afford the tools, I'd say get the smaller one and the tools. But you may find that you are good at this RDWC thing and that 5G pots are your limiting factor, so...
You would never fit that root ball I pictured above in 5 gallons for example. But that root ball is responsible for a huge harvest up top.
It's a balancing act with your checkbook making the final determination.