Personally, I love them. Games which let me build railways are extra awesome.
I now refuse to build any fortress now without minecarts.
But my problem is (insert joke here) that the dorfs are not as fond of them as I am. In other words, they tend to ignore them.
So how do you use them effectively?
Let's say your line (of considerable length and taking most of a year to build) extends from points A to G. All along the line (tunnel) you have ore being mined. Let's say A, B through G are all stockpiles with associated stops on your route.
Last time I played, dorfs would not take the ore to the closet stockpile (in terms of distance between stockpile and ore). Instead, each stockpile would generate a "fetch" event, and a dorf would be attached to it. Unless I'm remembering wrong, the dorf then fetches the closest ore to the dorf's location on being assigned the event?
Meaning that a dorf picking up ore at G is just as likely to manually haul it over the stockpile at A, rather than the stockpile at G.
Nothing makes me a sadder Panda than seeing the lovely minecart being ignored, and dorfs manually (or with wheeliebarrow) taking stuff to far-away stockpiles.
Without making a separate barrow for each zone (A to G - including a single stockpile in the zone) and manually assigning dorfs - then putting up with the haul cancellation spam that always results from such barrows - what can be done?
Postscript: I do feel the need to apologise for the anger management issues I experienced last time I posted (several years ago). These have been resolved with liberal use of lava and danger rooms, as I worked through my issues. Apologies to anyone I may have upset by being a douche. Fresh start and all that jazz.