Don't even think of putting a Mimaki with Triangle ink in your house unless you invest another $3k+ on a serious ventilation system, that will render your house uninhabitable.
If you're getting Onyx with it, use that, it's a killer RIP. Unfortunately though you can't print direct from an application, a wide format printer is in a different league than a desktop printer. You'd also be wise to use a stand-alone RIP computer separate from your design computer if you plan on doing any volume with it. RIP software is a system hog, while you can multi-task and design while something is RIPping, it'll be a big bottleneck.
Honestly, since you're new to wide format printing, you're going to be much better off taking the Roland, it's more "plug and play" than a JV3 with third-party inks. With the Triangle inks, you're going to have to write your own profiles as no "canned" profiles are available, and third party ink like that is also probably going to cause you some maintenance headaches if you're not running a good volume through it.