At the very least you would need two of those LED's to match the HID. A good rule of thumb is that you would want half the LED wattage to match an HID (assuming you are using quality led's in a suitable spectral arrangement). I also am not a fan of the UFO's, they are less expensive, but they are lower quality, and spectrally are not ideal imo. You will pay a large premium for LED (though some of that is just up front because you will save a bit on power and bulb replacements), so most people find that HID's are better for them. HID's have been tried and found true for 20 years, so they have that going for them too. LED's (at least for growing) is a new technology.