Well, you're absolutely right, lumens don't have the last word. That said, these LED flood lamps aren't the most efficient use of your money, imo, but they are a really nice way to get your feet wet if you're interested in the technology. Again, though, keep in mind that in order to fully supplant your CFL's with LED you'll want to just about match Watt for Watt. Perhaps this is why the lumen output looks so low to you? And try looking for a manufacturer that specifically states 42-45mil chips. If they state 35mil (or don't mention chip size) I'd say look elsewhere. Larger chips produce more light with the same power (less heat, longer life). If in doubt you could try emailing the eBay vendor. I think the larger chip size is definitely worth the extra $5-$10.
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On PAR, it's similar to the CCT values you're used to seeing with your CFL's. If you already know this stuff, no harm done, I guess, just skip it.
Warm White, ~2700k-3500K
These will have a good amount of Blue light in order to keep the plants from stretching too badly, as well as a very nice amount of Yellow, Orange and Red. They even have some FR in there fwiw. Best suited for flower, but can handily veg all by itself as well. The lower the CCT the better it will most likely perform in flower.
Neutral White (aka Daylight), ~4000k-5000k
More Blue light than Warm White, most likely a different Blue peak as well (shorter wavelength), less Orange, Red and FR, more Green and Yellow. If you bought a 20-30W flood light with this CCT for your veg room it might just hook you. Compact node spacing and overall just very healthy, happy looking plants.
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If you are at all DIY oriented/interested perhaps read on. If not, sorry for the madman ramblings.
100W LED drivers can be had for ~$40
100W multichip LED's (same light source as what's in the flood lamps) are $10-$20.
A heat sink shouldn't be too expensive, or hard to find. You could buy a generously sized extruded Aluminum heat sink from
http://heatsinkusa.com/
or an active CPU cooler such as
http://www.provantage.com/enermax-ets-t40-tb~7EMAX043.htm?source=googleps
or
http://www.ebay.com/itm/120W-Multichip-LED-Cooler-/271053717315?pt=LH_DefaultDomain_0&hash=item3f1c0f7f43
These fans usually run 12VDC x 150mA, or similar. Little wallwarts can be found with these specs for $10, or better, ime. Hell, you might even have an old charger lying around in this range.
These are kind of expensive, but are literally a snap to wire everything up (ask the LED vendor to solder wires to the chip and you don't even need a soldering iron for this project)
http://www.amazon.com/Wago-222-412-LEVER-NUTS-Conductor-Connectors/dp/B003T0PUH6/ref=pd_sbs_indust_6
After everything is said and done I would try to aim for $1 per Watt or better, and if you hit that you're in really good shape. Might be hard to achieve first time around, but if you ever wanted to make a second light you might have supplies left over.
