However, an interesting aspect of floating habitats in the Venusian stratosphere is that a terrestrial breathable gas mix (80% N2 / 18% O2 / 2% trace others) is a lifting gas that's about as effective as Helium here on Earth. (Venus's atmosphere is > 90% carbon dioxide, which has a significantly higher molecular weight than air.) And it's protected from solar UV and radiation to a considerable extent by the layers of atmosphere above it. So your entire balloon -- or, more likely, dirigible airship -- can be inhabited volume, rather than just a cramped gondola slung underneath.
Photovoltaic power might sound problematic at first in view of the long Venusian night (a single day lasts up to 116 Earth days), but at altitude there are strong jet streams and winds circulate around the equator roughly every hundred hours. So you're not stuck running on battery power for months on end, but you may need some maneuvering capability.
This is not to minimize the problems associated with activity in the Venusian atmosphere -- but it's not quite the impossible hell-hole it's been portrayed as.
