I converted my Cannondale T2 with a Dillenger front hub motor kit. My experience may not be applicable for you since I ride with my 6 year old grandson. Due to some recent physical issues I now only ride ebikes.
The conversion was pretty straightforward. I have this same unit on a single bike and feel it is excellent into the wind and up hills. We get by in the lowest assist levels, but if road goes or wind picks up we can increase assist.
The hub motor is 350 watts. Battery life depends on a number of issues, but it is as good or better than any hub unit.
Good luck.