Many of the links on their website are dead/have no information. Their "trade up" policy is not listed, that I could see. In their ebay ads, they state 15% restocking fee for non-defective returns. Well, a trade up would be a non-defective return, so would you pay the 15% restocking fee? Plus, what is current market price? You claim $73 for 1GB module for the MacBook Pro, yet they have ads for $189.99 on ebay for a 1GB module for the MacBook Pro. If you buy from elsewhere, like the Mushkin for $69.99 AR, then when you want 2GB modules you can resell the 1GB on eBay probably for higher than the trade price of the Omni modules, so you still come out ahead AND have better memory to boot.
Go read one of Omni's eBay ads. Pretty scary stuff. They claim to be a "certified OEM memory manufacturer for ALL major brands of computers." When is the last time you opened a Mac, Dell, HP, Sony, etc and found Omni Technologies memory installed? NEVER. They are not the OEM memory supplier for ANY computer manufacturer. That would be Samsung, Micron, Hynix, Infineon, and a few others, but NOT Omni Technologies. I love the warning near the beginning of their ads about legitimate sounding memory sellers, and then they sound just like what they are warning against!

And what is Hypervelocity memory anyway? Whatever it is, boy, it sure sounds fast, so it must be fast!

And look at the building they show. I'd be curious to know if they even rent a small suite in that building or if they are still doing most of their business out of their basement.
Omni Technologies is big on marketing and self-promotion, but take away the fluff and you are basically sticking the cheapest generic memory in your Mac if you go with Omni Tech.

Sure, it probably will work today, as other generic memory will, but do you want the hassle of downtime if you have problems down the road? And although they have a lifetime warranty, will the company be around for the life of your memory? All things to keep in mind when shopping for memory for your Mac.