We're planning to go to Mendoza from Buenos Aires for a few days. Is two days enough for Mendoza or is it worth going there?
Depending on how much total time you have I think it may do you well to stay a bit longer (maybe 4 days). It's a good city to walk around and see the restaurants and shops.
You will see a lot of mention of San Martín. You may find it interesting to read up a bit about him before you visit to get a better appreciation for the Mendocino respect for him.
Also, there are a lot of outdoor things to do around the area. I would encourage you to look into some activities that may interest you ahead of time.
Just a few quick thoughts...
You are going to LOVE Mendoza I would recommend having as much time as you can there- You can never get bored of the amazing wine and vineyard tours. Make sure you take Mr Hughs bike tour around the vineyards- It will be the highlight of your stay!