When is it ok?

[AKΨ_BRO@DSU]

Hey, lets say that your best friend has just broken up with someone they've been going out with for awhile and they randomly ask what did you think of the person the whole time they were going out. If you really wasn't diggin the person, is it wise to them the complete truth as soon as they ask you that? I know it may seem simple, but chances are that when people that have been together for a long time break up, they have a high chance of getting back together shortly after...and I think that not prolonging a completely truthful answer to that question would make things awkward if that were to happen. The last thing I would want is my best thinking that I'm totally against their relationship. What do you think?