This consideration will have a significant impact on the photos you end up bringing back. I prefer to travel alone if the trip is strictly photographic. Firstly most photographers are on the lookout for subject matter when traveling. That goes without saying. I drive very slowly in these situations while doing my best to accommodate other drivers simply out for a holiday. Frequent stops are a fact of life. Acceptable when you are on the job with another photographer but if you're traveling with family members - forget it. With interesting landscape its not uncommon for me to stop every few hundred metres or to sit somewhere and wait for conditions to change - a fog to lift, sunshine to come through etc. Few people sit comfortably through this process.
Photography for me is akin to a meditation process where you become reflective, observant and part of the nature you are exploring. It requires careful consideration and assessment. If your thoughts are occupied with the well-being and mental state of your companions you won't be able to give this process its due attention.
Other things to consider are food and bathroom stops. A certain category of people like to stop more frequently and tend to their needs. Iceland as an example has relatively few places where you can stop and relieve yourself with privacy. There are also times when I went without a substantial meal for the sake of getting shots I really wanted. Following an afternoon spent in the 'wilderness' I arrived back to the accommodation late and happy to hit the sack knowing I had a good days shooting. There are certainly amazing scenes you come across that will lift the spirits of fellow travelers but it may not be enough to keep everyone's mood up for the length of the journey. Consider the extra expense and freedom and travel alone if you want to maintain sanity, good mood and come back with a bag of shots you'll be happy with.