I have not taken the TACV flight but I know people who have. It is frequently late and uncomfortable but it also by far the quickest way from the US to Cabo Verde. If you book through TACV's Boston office be aware that they only accept cash, cheque, and Amex.
Do not go to CV expecting it to be "African". It is much more similar to Brazil and parts of the Carribbean culturally than it is to mainland Africa.
Hope this helps...