Depends on what you play the most.
If your a lover of Sniping in all TD's and whatever mode, the DSR-1 is ofcourse a good option.
If you love the recoil of the Tar21, you'll have alot of heashots, though Tar is not for far distances
And as last then we have the type89, but i would not choose that once, since you can get much better than that weapon, it might be good, but you still have to test alot of guns then.
I would pick the DSR.
Regards
Middnight