The Ultimate series had a few releases but all were hardwire locked to the Telstra network. No amount of love nor money will unlock them. I owned one of the first and it used any Telco sim piggy-backed to the Telstra network. Like oldbloke's it refused to power up. That was possibly my fault because connected to USB 24/7. Some models in the later LTE wifi modems can be unlocked for use on other networks but may not use the bands your chosen non Telstra Telco uses. I haven't tested mine with other Telco because I only have Telstra sims. Whether a modem works better than a phone hotspot depends on your phone and whether you use the phone at the same time.
Put wifes sim card (aldi) in my ph and got about 10 download in house. Put mine back, about 8mbps download. Aha fixed. Weeeelll no, an hour later back to about 2mbps. Work that out. Now 2 hours later removed and replaced my sim back to about 6mbps? Fairly usable on laptop. Its a puzzle alright.
-- Edited by oldbloke on Wednesday 19th of February 2020 02:09:30 PM
I might be dreaming but since the ph call to boost/telstra and the sim swapping it does seem have improved. Just checked and 7mbps download. Yes there is no doubt that telstra customers get a faster/better service. I wouldnt be surprised if they can even adjust individual mobile speed if they want. e.g. neil had complaind so up my speed 25%.