I'd go for it. We live in a top floor (duplex) apartment and since the Swiss like to heat to Sahara temperatures, despite having the largest flat we have the lowest heating bills thanks to all that heat rising up.

In summer you will be hot whichever floor you're on, but perhaps by not being "boxed in" your flat may be a bit cooler, so unless you have a/c I wouldn't worry too much about for what is usually just 4 - 6 weeks of very hot weather.

One other advantage is you won't risk noisy neighbours or children running above you, people dropping things on your balcony and less lift noise as you're on the last floor.