For better or worse, the majesty of the national broadband network means that almost every premises in Australia has access to a broadband connection that delivers roughly the same basic performance options regardless of retail vendor.
The problem is, however, some premises are more basic than others.
What's potentially on offer at any particular location will be a subset of what NBN calls Traffic Class 4 (TC4). The available speeds will be limited by the connection technology that's in place. What each vendor then offers to sell will be some subset of that.
Typically, a retail vendor will offer a plan at 50Mbps download and 20Mbps upload speeds (50/20), and one at 100/20. A post-installation line test will confirm the actual speeds that can be delivered.
Getting anything faster on the NBN relies on the luck of having better technology provided at your location, such as fibre to the premises, or at least to the basement, or HFC. In the case of FttP, speeds up to 1000/400 might be available, depending on the vendor.
This is why every vendor will ask for your address before even thinking about offering higher speeds.
If your business needs more than what your luck-of-the-draw NBN can provide, you have two choices.
Under the NBN Technology Choice Program, you can pay to upgrade your location to full fibre. As the company warns, however, "costs can vary greatly" and that could easily run into the thousands of dollars, especially outside inner city locations.
That said, under the NBN Business Fibre Initiative, "an estimated 90% of business locations within the NBN network footprint" are now eligible for a connection to the company's Enterprise Ethernet plan with no upfront connection cost to your provider if you sign a 36-month contract.
Or you can look at what the vendors themselves can provide using their own non-NBN connectivity options. Once again it's all about where you are and what gear they already have in your area.
Either way, if your business is located in premises you rent or lease, you'll also need to check with the owner to confirm that you're allowed to do any work required as part of the installation.