Very much a subjective decision.
I'm a fan of the UniFence and am glad that the fence on my MM slider has some similar qualities. It's harder to "roll your own" jigs, however...at least with the stock fence face. But there is an aftermarket fence that fits onto the UniFence structure for when you want to accommodate that need. The most endearing quality of the UniFence and similar is the ability to move the fence parallel to the cut line or use a smaller piece for what you only need it as a stop. (Clamping a block to a "standard" fence certainly works for that, but it means you have to remember to account for the thickness of the block when setting the fence position) I also like that the face of the UniFence 'is' the measure point on the scale.
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The most expensive tool is the one you buy "cheaply" and often...