That's a good deal, but it is up to you to decide if it is the right bike. Technically it is only a very minor step up from the quality of your Jamis, which is a $1200 bike. But, as you know, it is a very different bike.
Personally, if I were shopping in the $1500-$2000 range, I would be giving serious consideration to an all-carbon bike. I would ride a couple of these for a few miles, and then come back to an aluminum/carbon combo, like this Cannondale, or a steel frame, before I would buy. You don't want to buy another bike and then immediately have regrets. There is always some second guessing after buying, but if you left something on the table, like not knowing if you liked full carbon better, then it will knawl at you.
I do think the Synapse is a nice bike. I rode a Cannondale with their SAVE carbon fork and it did a good job of smoothing the ride. And I know the Synapse has a comfortable geometry.
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"Too often I would hear men boast of the miles covered that day, rarely of what they had seen." Louis L'Amour
There are two types of road bikers: bikers who are faster than me, and me. Bruce Cameron - Denver Post