A while back I asked myself the same question and did a little research, I found this:
On one hand, we have Buffer. Buffer is good if you want to manage from 1 to 4 social media profiles and up to 10 if you want to get the "awesome upgrade" which is worth $10/month or $102/year saving 15% and on the other hand we have Hootsuite, Hootsuite supports 3 social media profiles for the free version and upgrading to PRO you get the massive increase to up to 50 social media profiles (remember in both this includes profiles, business pages, and groups) the upgrade costs $9.99/ month and if for some reason you need more than the 50 profiles that they offer you can add 10 extra for an extra $10/month.
The biggest difference in the free version lies not in the fact that buffer gives you the extra profile but the AWESOME app directory that comes with Hootsuite. They currently offer 143 apps from which 77 are free to use (some have a monthly price, this will vary from app to app). Among the apps, you get YouTube, Analytics, Tumblr, Evernote, just to name a few.
Now let me tell you what Buffer gives you in terms of social media profiles:
Twitter
Facebook (supports profiles, pages, and groups).
Google+ (only supports Google+ business pages).
LinkedIn (this includes profile and pages only).
Pinterest (This feature is new and you can try it for 7 days, after that in order to continue to use it you need to upgrade).
Now let me tell you what you get with Hootsuite:
Twitter
Facebook (supports profiles, pages, and groups)
LinkedIn (this includes profiles, groups, and company pages).
Google+ (Google+ Pages only, not profiles)
WordPress
Instagram
Now if you see even when you can link one more profile with the free version on Buffer, what you get from Hootsuite in terms of variety outweighs that one less profile. In terms of upgrades, Hootsuite is hands down the best by far.
Now I've used both and the one I still use and recommend is Hootsuite, that App directory is just too good not to use it.
Hope this information helped you and that you choose the one that suits your needs best.
Blessings,
Jonathan Nunez