The Taz and the Prusa can produce essentially identical prints when they are both dialed in correctly. the Rocktopus prints are ran at .35 or .4mm layer heights. You can easily install a smaller nozzle, the only restriction is not using a non electrically conductive nozzle (so no Olsen ruby, nozzle X remains an unknown)
Larger filament is a bonus in my opinion because it allows you to deliver more plastic to the nozzle with a heat pattern that is easier to control. Especially if you mod your Taz for higher speeds, printing north of 130mm/sec is easy with the larger filament. It is more difficult with the smaller diameters because you end up with less consistent heats and more issues with filament breakage. The upside is much higher filament type availability. You can also easily mod your taz to accept 1.75mm filament if you like, or source the newer style Titan aero toolhead in the 1.75mm variant. This thread has some pictures of my modified Taz 5 that were printed on a 0.1mm nozzle for use with leather stamping (.05mm layers) https://forum.lulzbot.com/t/taz-prints-tiny-too/3871/1 That was a few upgrades back, so I could probably go smaller now if I wanted. A taz 6 is basically a Taz 5 with upgrades, though admittedly mine does have quite a few mods attached to it. A stock taz can certainly get close to that detail level with the right nozzle.