From Crampton's A Concise History of Bulgaria:

They [the janissaries] also played an important part in the imperial administration; at times they remembered and favoured their home villages, and there are even records of villages requesting that the devshirme be levied on them in the hope that in future years such favours would be paid, but for the most part this tax in human kind was a dreaded feature of Ottoman rule until the late seventeenth century; the last full levy in the Bulgarian lands was in 1685.

Completely anecdotally, Bulgarians do not remembered the Ottoman period fondly. They call it "Турското робство", which is usually translated into English as "the Turkish Yoke", but could also be translated as "the Turkish slavery" (роб means "slave"). It would not be unusual to hear a Bulgarian say something like "that was when we were the slaves of the Turks" when referring to this period. I don't think any positive effects of the devshirme balanced out the negative.