Yes, but wait a little, i have already reported a little mistake in Joomla 3.5 Github files(not important for VM), so i think on production site, it's better to wait some weeks.
And not only siteground provide php7.
I have opcached,memcached, nginx, any php release i want, on a french localised VPS for half the price of siteground or at same price with a bigger SSD and more memory.