No reviews for tactics Imrahil? Well he's not really popular, either in this or his leadership form, but I find his unique ability incredibly useful with combat-heavy quests and encounters. So right off the bat, you get a strong hero with a great range of stats- the 2WP is nice in a sphere that averages less than that. He's a capable defender, and can deal a good bit of damage, too.
But his real strength is his ability, combined with his three traits that make him work in a variety of decks: I've successfully used his ability in everything from a Gondor tactics deck to a leadership/tactics dwarf/Gondor/Rohan hybrid deck- which worked because most, if not all of those allies shared at least one trait with our venerable prince. I've even teamed him up with Na'asiyah with good effect.
I'd be hard-pressed to pick between leadership Imrahil and tactics Imrahil, but if I had to pick one, I'd give a slight edge to this incarnation, as I've personally found his ability to be an absolute lifesaver and occasionally a game-changer; being able to instantly bring out reinforcements as needed is high utility, and it gets even more useful when paired with the leadership access to resource generation and management.
Again, remember that his ability can work with many deck and card types, including many elves, dwarves, etc. so he lends himself well to experimentation! Starting out with the Gondor, Noble, and Warrior traits is great, but throwing attachments on him that bestow traits- like Sylvan, Noldor, Rohan, Outlands, etc.- make him potentially suitable to such a wide variety of decks that I'm really surprised he isn't more highly-regarded. Give tactics Imrahil a shot; it's a lot of fun experimenting with him!