That's about $925 U.S.D, which strikes me as being fair value for what they're offering you. I base that on KEH prices in the U.S. which are generally quite fair for used equipment. If you look here, you'll see what I mean. Dead Link Removed KEH equipment comes with a warranty. That's always handy. They also over rate their gear. I've purchased bargain grade equipment from them that in my view rates as Excellent. KEH also sells equip. all over the world. If you want the name of a good representative there, drop me an e-mail.
There are other things I'd consider here though. I have a 553 ELX which for 18 years has been an absolute workhorse. I mainly use it for shooting portraits. So, ask yourself what you need a motor drive for and maybe consider a manual wind body that has a rapid-wind crank. They're quite fast too. The diff is you don't have to take your eye off the viewfinder with a drive. You'd save some bucks doing it that way.
Also, consider the cost of additional lenses. While a 150mm is an excellent lens for portraiture among other things, you're probably going to want something of a more normal focal length like a 60mm or maybe an 80mm. Extra film mags are pretty essential as is a reliable meter and don't forget filters that are robably not compatible from your SQA. 60mm bayonet are standard Hasssie filters although you can save megabucks getting 67mm threaded and reduce them to 60mm bayonet. Oh, and a lens shade. Waist level finders are good but a stove-pipe magnifying hood is better especially since they provide diopter correction.
Worth keeping the Bronica? Again, I think it depends first on why you want to change ? Before I changed to Hasselblad gear a long time ago, I used Rollei, Mamiya C220 and Nikon F-2s. I'm a photojournalist so the equip. has to be reliable, reasonably rugged and capable of doing what I need it to do. I have to say I'd never go back but I know too, it's not necessarily the camera that produces great images, it's the nut behind the wheel, so-to-speak. So will a Hasselblad make you a better photographer (which people often ask me) and I tell them not necessarily. But the system itself offers a broad range of bodies, lenses and accessories that may make them better equipped to find photographic solutions. Certainly it can record wonderful images but in my time, I've produced some real clunkers with it too. LOL!!! Zeiss glass is also top shelf lens quality. Pricey, but excellent.
Have you seen Ernst Wildi's books "Hasselblad Manual" or "Medium format Photography"? Worth looking at before you score one of these and having them as references after you get one.
Sorry to be long-winded here but there's a lot to consider when you're changing systems.
Meanwhile, take it light.
Mark