To add another reason why the DTB might be superior for your needs, They are now available (at least in some locations) in a single "Hyperfire" pack.
Overall, depending on what you want, you're still probably better off getting the set of two--the current set comes with two Hyperfires, two Reflex/Eliminator-alikes, two vests (which make great wall-mounted targets if you pin them up) and two pairs of safety glasses for $40. The individual pack (at least where I've seen them) only gives you one each Hyperfire, vest, and glasses and costs $25. If all else fails, find someone nearby who's interested, each pitch in $20, and split a set. That's what I did.