If you get the 900 you might want to disable to overheat shutdown, do it through the menu. It seems overly sensitive even with the latest firmware, once it kicks in you can't disable it or use the flash at all until it cools down. A real problem if you don't have a second flash on hand.
You still get the warning beeps and on screen warning but you can continue shooting. I've driven the 900 until the front fresnel lens starts to bubble, doesn't hurt the flash but I don't care about cosmetics just need the job done. Using a reasonably high ISO will reduce how hard you have to run it and external battery packs also reduce temp. And have the benefit if reducing recycle time.
Not sure if the 700 has the same issue with the thermal cut out but you might want to check. Besides this I still think the 900 is an awesome speedlight, much better controls than the 800, maybe the 700 has a similar layout?