There's precious little variance when it comes to USB modems, because when it comes down to it, there's only a few vendors that Australian telcos tend to use for their modem designs, and there's not that much you can do with a USB stick loaded with electronics anyway. Optus' current 4G LTE 1800Mhz USB Modem is labelled as the "Premium" 4G modem, but that's a meaningless title, given that it's Optus' only 4G USB modem. Still, as USB modems go, it's a reasonable piece of kit.
Optus (and competitor Vodafone) have for a very long time been using rebadged Huawei kits, and the E3276 Premium 4G Modem is no exception. The USB plug flips up from a small switch, and the same side houses a slide-back cover that hides the SIM card slot. One nice aspect here is that the slide back mechanism is solid, but easy enough to activate, whereas many USB modems rely on you having a long enough fingernail to pop the casing open. If you don't want to scuff your nail polish or simply don't have long fingernails, the E3276 Premium 4G Modem's approach is a good one. But apart from that, and the fairly obvious Optus branding, the E3276 Premium 4G Modem isn't really premium — it's just ordinary. As with all USB modems, there's also a slight risk when using them for mobile purposes, simply because it'll stick out of the side of the laptop you're using with it, although the hinge on the premium modem does solve this, as long as you remember to flip it upwards.
Optus' 4G offering, at the time of writing, consists of a number of 4G LTE 1800Mhz sites across Sydney, Melbourne, Perth, Brisbane and Adelaide. Regionally, it covers an area around Newcastle (where it held its first FD-LTE 1800Mhz trials) and the Gold Coast, but that's it for now. Optus has announced plans for an TD-LTE network in Canberra, based around the spectrum it acquired as part of the Vividwireless deal that's expected sometime this year, but it's not yet clear whether the E3276 Premium 4G Modem will be firmware upgradeable to support that network; it seems wise to suggest that it's unlikely. As such, the E3276 Premium 4G Modem will only work at top 4G speeds across limited metropolitan areas, as distinct from Telstra's LTE rollout, which encompasses a wide number of regional centres. Depending on how you planned to use it, that might not be a problem at all, of course.
Optus has for a long time used the base Huawei connection software with its USB modems, and the E3276 Premium 4G Modem doesn't differ from this pattern. That's not without its challenges. Our test laptop had previously tested an Optus USB modem and still had the software installed, which led to some confusion when it automatically loaded, but couldn't see the connected modem. If you are upgrading from a previous Optus USB modem, it's wise to do a complete uninstall of existing utilities, and then a fresh install, which was how we got the E3276 Premium 4G Modem to work.