Mapstat and Civassist only give you info that you can already get in the game. I tend to use them in spots.
Say I want to know what techs are available. I could go to each civ and contact them for a trade and get the data. It is so mych easier to comprehend if it is all there in one spot at once.
Same for alerts. You can find all of them on your own and I did until about 2 or 3 months ago.
I do not load up Civassist and leave it up. I close it as soon as I see what I want. I may use 3 or 4 times in a game. It has a lot of feature, most I have not even found out about.
They have disable use in MP games as I understand it. So it helps mainly to save time and work. If you have more than 8 civs, it really helps.