What is wrong with using syrup in the feeder?
It really needs painting inside - otherwise it
may well weep. Bates discovered this last year when the wasps discovered the seeping syrup and started chewing in through the poly.
Bees tend to drown in it. Maybe the right painting would help. Using the mini-QX should remove the risk of Q drowning.
You can't clean the feeder out without removing all the bees from the hive - which tends to be a particular problem for owners of just one nuc …
And it IS a pain to clear out the feeder if the bees decide to build comb in there. Now if you allow Q into that comb, you really do have an awkward problem. (Using the QX should prevent that BUT if using fondant in there for the winter, do you use the QX (risking the colony) or leave it open and risk the cluster moving it (and building comb)? (Don't risk the colony!)
And being to the side, unless you have masses of syrup in the thing, its a long separation away from the bees - its a longer way away (and colder) than a feeder above the bees. Which matters more later in the season - like now.
I've concluded its simply better to close the feeder off and pretend its not there.
Overall, despite its imperfections, its still my preferred nuc box.