To what extent SVG is hardware-accelerated entirely depends on the browser. Chrome was quite late to the party of making drawing fast and it often shows (it redeems itself with a fast JavaScript implementation in complex applications that have a lot of rendering and computation). But the raw drawing (of SVG, not canvas) has been a lot faster in IE for quite a while.

I'm working on a graph drawing library at work and for our web product we rely on SVG. In my experience the performance is good enough for our purpose at least (graphs are a thing that becomes more or less unreadable as the number of entities go up, so useful graphs tend to only have a few hundred nodes/edges on the screen at most; and that's still effortlessly possible with 60 fps interaction). Where it gets annoying is that especially Google clearly doesn't really care for SVG. It's not used (much; or only with static images) in the top 500 sites or whatever they look at for optimising their browser, so they frequently break things with rendering that come to bite our customers.