Both using the same tm unifi backbone, so no difference in terms of network quality.
I was using unifi 300mbps and recently changed to digicelcom fibre. Their technician only change the modem without changing the port or router originally set by unifi.

And i think digi fiber is arguably the cheapest of the main telcos. $100 for 300mbps. Oh wwit, this one requires a postpaid under digi/celcom iinm.

So next cheapest plan is maxis fibre. Rm145/mth for 300mbps plan but free for the first 6 mth.

To be honest, I don't know.
I did ask the technician that came to install my router, but he says he doesn't know as well.