It has amazing music and a ton of snazzy special effects going on, but I prefer the more balanced difficulty of TF3 even if I don't enjoy its OST nearly as much. I'd even go as far as to say this one is a tad overrated after playing it through, but it's still a good enough time.
Best path for anyone trying to keep shields- ruins>desert>strite>air raid
Best path for anyone trying to keep shields- ruins>desert>strite>air raid