I like that we are able to do our own thing, with no limits of what they can provide us or how many people their team has in house! They have helped me so much by being very responsive when it comes time for projects which require my input immediately after signing off - even if its not working right away (as opposed from other companies where you're just told "It's fine!").
Sometimes there isn't anything specific i dislike about them but sometimes things may seem slow at times as well because some tasks take longer than expected due mainly towards communication issues between myself & client side teams regarding timelines etc.. We've been using seize since 2013/2014 during early stages until now; however never had any problems till date nor will ever face one while doing business together- all good thus far though nothing negative yet either!! Great experience overall especially considering.