Our children are 21 months apart. I used a Bjorn carrier, but a double stroller was still essential for us. My son was still at an age when he needed to nap even when we were out and about (hard for a little boy to do that walking or with a sit'n'stand). And there were times when I did not want to wear my baby girl (such as trying on clothes and eating lunch). I couldn't have lived without my double stroller.
I had a Maclaren and love the side-by-side strollers (loved watching my kids interact with each other). I don't know much about the BOB in partucular, but I can say that if you intend to take it to the mall or the store or a restaurant--anywhere with a door--you will want a stroller with a width smaller than 30 inches. Otherwise you will have a problem fitting through many doors easily.
And about spending the money on a good stroller--remember that a well-made, well-kept stroller can be resold when you're done. I bought my stroller slightly used at a discount, and then recovered much of the cost by reselling it later. I am so glad I spent a bit extra on a GOOD stroller, rather than trying to save money on a chintzy one that I would have been frustrated with. (I had actually thought of going cheap by joining two umbrella strollers together. Wow, I would have ended up hating that!)