If you use vodka, be it flavored or unflavored, the damn drink does not even closely resemble a "Caipirinhas". The raw cane distillate that gives the drink its character (and the more than subtle hint of rotting vegetation and spilled kerosene) is an essential ingredient. Even the rawest of branded white rums don't quite offer the essence. Now "Cana" (little curlicue over n) from Paraguay is a suitable substitute.

In general, commercial flavored vodkas except for old familiars such as Pertsovka and the Polish brand with buffalo gress simply don't match simply adding a bit of the fresh ingredient to a decent vodka. One fancy brand "au poire" recently offered me as a sample tasted of nothing so much as bargain vodka dosed with canned pear nectar.

Natural infusions work pretty well, and combined with simple syrup some "better than store brand" fruit cordials can be made at home. Meyer Lemons and bitter oranges from Seville work well, while most limes have too much residual bitterness for infusing (and besides, fresh "key" limes are widely available, inexpensive and a fresh joicy complelemt to coutless mixed drinks, some of which fall flat without this essential component, especially Margaritas, Mojitos, G&T, Daiquiris, Capis, and several more).