Yes, it's its own format, very simplistic and basic, no fancy superfluous nonsense. And $1300 would allow you to build up a rather sizable system. There are some drawbacks, however...for one thing, the AE system only uses positive CVs in a 0 - 5V range. This is very much compatible with other synth gates/triggers, but the CVs and mod signals do require some range constraints. Fortunately, there are two solutions: 1) the AE system has the 4I/O module, which not only handles audio input/output, but also handles voltage constraint, or 2) a Soundmachines' Nanobridge, a small $30+ board which gives you 14 channels of CV/gate/trig I/O with constraining reference voltage from the AE itself. The other drawback...if you're not used to working with them...are the Dupont patchwires. These are typically what you'd find in circuit prototyping work (one reason the AE gets used as a DIY development bed: the direct interconnectability with prototyping boards) although a few synths do use them...a number of Bastl devices, various Folktek modules and their Mescaline device, the Korg Volca Modular, etc. But one also has to keep in mind that, unlike 3.5mm or 1/4" patchcables, Dupont wires do not have a ground connection, so like you'd encounter with a Serge system, Kilpatrick Phenol, etc, you'll have to establish a ground-plane connection to any other devices you'd be patching the AE to.
Best thing I could suggest would be to go to https://www.tangiblewaves.com/ and have a better look. The forum there also has quite a few users (myself included) that range from players all the way up to module designers.