I envy your lothlorien army
how long did that take to build up?
Anyway, on to the uruk-hai. Well i'd say there probably the second best evil faction( only second because mordor suit my evil tactics the best: field masses of orcs
) and yes, that strength 4 really helps. They also have a good range of troops such as:
Phalanx:extremely effective against cavalry
Uruk-hai warband:high strength and defence
Uruk-hai scout warband:still good defence,high strength and move of 7''
Warg riders: high strength, fast moving and prowlers special rule
Beserkers: extremely good on the charge
and then the odd troll here and there
Then Lurtz and saruman are probably the best isengard heroes:
Lurtz has 4 might points and some very nice special rules
Saruman has mastery 3, touched by destiny and voice of saruman(which means that enemies wishing to charge saruman's formation must role a dice and get above 3 or the charge automatically fails)
So yes, if you use them well and select good troops, then Isengard would definately be a very good choice
(oh and isengard also have some very effective battle hosts, but i don't have my battlehosts book with me right now
)