Loyalty - it really does pay to not switch CRM tools every few years. I'd recommend building a good rapport over a number of years with your chosen platform, the benefits can often outweigh the small upside of saving a few £'s. This does not mean you do not challenge them when the tough questions come round.
Customer focussed - the support I've received is second to none. After the first year of using Sailthru, the main reason for signing up to a second term with Sailthru was due to the timely support I received in the critical first year of setting up Sailthru.
Staying one step ahead - Sailthru values feedback, they are always looking to find out what makes us marketers tick, and with that build solutions to fit our needs.
In the four years I have used Sailthru I have seen the tool make huge steps forwards, mainly in adding new features, revamping the look and feel of the product.
Also, ever wondered what is the best time to send an email? Well the answer is, it's different for each customer/user. Sailthru has a tool out of the box which will help you personalise the send time for each customer.
Honestly - nothing comes to mind.
They bring great customer support (strategic and tech) which is super responsive and have a huge set of training assets.