In the end, Itsycal is the best utility of its type that's available, but I'd give it 5 stars only if its layout were more configurable.
In a different vein, though, Itsycal's two donation options are Square Cash, which works off your debit card, and PayPal, which requires your paying a fee if you use a credit card, both of which are, therefore, free to the developer.
Huh?
Mowglii's benevolent beginning comes to an unique (in my experience) and mercenary end which is hardly in the spirit of donationware.