It supports radio via their AirTTL system (built-in), comes in E-TTL versions for both Canon & Nikon (and they also have AirTTL radio transmitters for both systems - which is the same one they use with other Profoto systems such as the Profoto B1 & B1X, etc.). It has a built-in modeling light (I'd have loved to have that back when I started shooting at dark wedding receptions).
I'm not sure how it compares to other high-end speedlites (e.g. from Canon & Nikon) because speedlites are typically rated in "guide number" (because the reflector is fixed - it's not a bare tube) and studio strobes (which typically are bare tube) are rated in watt-seconds because the "guide number" you get really depends on which modifier you use.
It took a bit of digging... but it DOES have an exchangeable Li-Ion battery pack. Extra packs are already pre-orderable at
B&H Photo for $99.
But there is another fairly distinct advantage...
Suppose you are doing "event" or "on-location" photography and you want a side-light with a strong flash ... something like a Profoto B1 ... but you also want an on-camera flash. Since the AirTTL is built-in, you can use this as your "on camera" flash and use the B1 as the "off camera" flash since the radio technology is built-in and the same.
This has some nice advantages for pros (who want to add an on-camera flash to an existing Profoto "on-location" lighting system (and I'm really thinking of the B1 or B1X system). If I'm a photographer who only wants a single on-camera flash and I'm not looking at my flash as just being one part of a larger flash system... then there are lots of other flashes on the market that will probably do the job for less money. The A1 is about $1000. It's a nice flash, but it's more than even the flagship Nikon & Canon brand-name flashes.