I don't own any savage orcs unfortunately and don't plan on making that purchase any time soon. Also there will be new players (relatively new anyway especially to this points level, myself included) so am not expecting that many GT lists to be there (with the exception of a VC player but he's a dick anyway and I'll happily hand him the victory if it means that every move I make is not measured to the exact millimetre - no exaggeration)
I love my squig herds, if I had the money (or if the rumoured plastic squigs are true - guessing not) I'd run two hordes of them. I know what happens to manglers, they typically are targetted quickly which suits me as it leaves everything else rather exposed and the units that pop them are typically more expensive then the manglers themselves.
I prefer the Rock Lobba to Doom Divers myself, mainly because people don't tend to run the typical Doom Diver targets (Chaos Knights ect) the players here are kinda hung up on hordes to the point that my MSU Wood Elves run circles around them and have not lost a game for 10 or so.
The level 4 is slightly concerning, mainly due to miscasts I never really have an issue with hiding him behind something when combat is met. Ideally I would like to give him a 5+ or something probably in favour of 10 or so of the Ng's.