It's best when dealing with several clients, products, and creative materials. When dealing with a high volume of creative materials to be trafficked to several different networks, I'd recommend Adstream.
I personally am not involved in the decision to renew the product, but I had only positive experiences with the product and thus would recommend its use and renewal.
Smaato has a UI where you can control your line items on the traffic you want to receive. That is a key unique selling point that other SSPs don't offer. Most of the items that you will need like reporting can be done on a self serve manner and that is a big plus, specifically for changes that need to happen really fast and you don't need to deal with account managers that may take some time to answer emails.
Smaato's account management team is very professional. They are quite fast in terms of customer support, which is very helpful. One item that stands out is that they are willing to understand what you need for each campaign and what is the best way to move forward. They don't just jump quickly into trying to upsell more of Smaato's products (audiences, data) like other SSPs do.
I love Adstream because it does a great job at streamlining its ads to different components and different industry providers unlike Apple iAds and Google AdMob. It also is very helpful for a new business like myself to reach different audiences and hopefully generate some revenue from these types of diversified ads.
Smaato has better anti-fraud controls than most exchanges. Even if the inventory ends up being a bit pricey, I am more comfortable running campaigns on Smaato because I know there won't be any issues with the clients claiming refunds for invalid traffic. I believe that as the industry matures, other SSPs will follow suit and prices will increase along with the board.
We have seen prices a bit high, thus reducing profitability
However, the vast reach has allowed us to get more budgets and fulfill them so the net effect is positive.
We have been able to run campaigns that targeted the same user on mobile and desktop by running with Smaato and that has allowed us to get more budgets from specific clients.