I use the PIAA 1200 (ION-Crystal) lights primarily for being seen. They cast an "Amber" color and have a lens that extends from the housing 1/4" so there is a bright ring around the front of the housing. Especially useful for being seen from the sides. I run them 95% of the time day/night and they have lasted four+ years now and 52,000+ miles. Unfortunately they discontinued this model, but they can still be ordered (I think) direct as long as supplies last for half the original price (or about $120 for the whole kit, includes switch and harness).
I don't know enough about the Moto-Lights, except what I've seen in my rearview mirror. Great for being seen, but, the lower something is mounted the more shadows is will make on the road. Good for off-road stuff, but I'd like to see what's in front of me, not what is that dark spot just beyond, Oh Sheeet...
If you are really after SEEING at night get the Hella or PIAA (HIDs). A lot more money but in the end, isn't it about seeing what lurks ahead?
The other point someone made is that caliper mounted lights "Don't steer into corners any better or worse than frame mounted lights, becuase you don't turn the handlebars far enough to make any difference at speed".
I'm still hopeful that BMW will put their auto-levelling, point in the direction you're going Xenon lights they use on their cars into a MC.
If it's just about being seen from others' I really think any AutoZone/K-Mart lights will do and save you a bundle in cash.