I bought the M4 air given that the consensus was also that it was the best value for 1k, but I ended up returning it and went for pro base model for a few reasons (still valid for M5 AFAIK from a bit of research):

- pro motion (120hz screen).

- better display brightness which is important when there is a bright sun outside.

- 1 more USB-C port and HDMI port (no dongle hell).

- 20% more battery life.

- This is more personal, but 13" is too small and 15" is too big, so 14" MBP worked best for me (~25 HFOV with a stand + KBM).

It's hard to justify saving 400 bucks given the gap between the models, but the decision is closer since the air has 16GB memory by default since M4 AFAIK.