The Boardman feeders are useful once the weather is warm, especially for
feeding new nucs which have been transferred to full-size hives in spring.
The visibility of the syrup level and ease in refilling (or just replacing
with full jars) are both pluses.
 
The mayo-size jar for such feeders is too small, IMO.  I have switched to a
larger round glass jar, closer to 1/2 gallon size (perhaps somewhat less),
which has the same top opening.  These will last much longer between
feedings.
 
If you have Boardmans and you have given up on them, you might try the
bigger jar and find them very serviceable in many feeding applications.