I would suggest that you stick with Jamis, but go with a less expensive steel-framed model, that can be upgraded beyond the level of an Aurora.

However, the Aurora is somewhat of a touring/road bike, whereas the Vitamin and the Avalanche are both hybrids. In this case, go with the Jamis Coda Sport which cost less than both of the previously mentioned hybrids, but can be upgraded to the 105 level in time. An upgrade which will surpass that of the Jamis Coda Comp and the Jamis Aurora, as well. Since its frame is steel, it will be certain to render service for decades, if well-maintained.

Good Luck!

- Slim