Eldar with a wraithlord or two.
Sisters with meltas and mech.
Guard with vanquisher or two or basilisk battery or lascannon heavy..
Blood angels with jump pack melta bomb troops.
Dark eldar with dark lances and raiders.
Nids with fexs tooled for CC.
Demons with greater demon and 3 prince spam (very popular at tournies)
Dark angel double wing spam.
The list goes on bud, needless to say these armies will ruin your day and are quite tournie popular.
Go for your list it will probably be unique, but dont expect it to crush all comers. The 3 raider spam has been around for years so most gamers are well aware of it.
There is an old saying "dont put all your eggs in one basket" your list does, so it may win by lots but may lose by lots too.
A squad of marines needs 10 kills to get rid of , a vehicle just 1.
Good luck and have fun