Light Quality
I love this bulb! The light from this LED is exactly as advertised--very bright, omnidirectional, and in the same pleasing color of incandescent bulbs. Even my very picky sister, who claims CFLs give her headaches, is satisfied with the L-Prize light. There is absolutely no flicker or hum to bother her, and the color faithfulness is fantastic. Its 92 CRI (Color Rendering Index) is much higher than any competing LED or CFL in the A19 warm white form factor, and very close to the maximum 100 on the CRI scale. Cheap, imported LEDs can have really horrible color, like early CFLs had. If you go with any other bulb, always look for an Energy Star seal of approval, which guarantees at least an 80 CRI (the L-Prize bulb will get Energy Star status very shortly). Color temperature is different from CRI, but just know that it produces warm, yellowish light exactly like an incandescent bulb, not harsh blues or ghastly greens like first generation LEDs and CFLs. And this bulb is very bright--at 940 lumens, it's 17% brighter than the 800 lumen output of a 60W incandescent.
Drawbacks
There is a very slight (but noticeable) delay when turning it on--perhaps 1/5 of a second. It does come on at 100% percent brightness though, with no 'warm-up time' like CFLs need. This bulb can be dimmed smoothly down to 10% of output, but the light quality suffers. Instead of transitioning to a romantic and orangey candlelight glow, these get a progressively harsher, unflattering color. I recommend just using them close to full brightness. Also, like most LEDs, these should not be used in totally enclosed fixtures or you risk shortening their life. Finally, some may find the appearance of the unlit bulb ugly if placed in unshaded fixtures. Personally, I think it looks cool (and it's a great conversation starter). The light yellow panels and white body look much more attractive to me than the bare LEDs and exposed metal fins of other LEDs' heat sinks.
Price
This is by far the biggest drawback. Fifty dollars?! Is Philips crazy? Well, depending on where you buy this bulb, maybe not. You see, some local electric utilities are offering rebates of between $10 and $25 when you buy this bulb, applied automatically at the register. No rebates for online retailers, unfortunately. If you can find this discounted at your hardware store, buy it! Not only is the quality of light great, the efficiency of this bulb is unmatched. It gets a whopping 94 lumens per Watt. Compare this to the measly 13 lm/W of a 60W incandescent, or ~64 lm/W in current CFLs or LEDs. It's 50% more efficient than ANY other bulb of its type. Wow!
Whether that efficiency is worth it to you is another matter. If you're satisfied with CFLs or cheaper LEDs, the efficiency gains of this bulb will not offset the $50 bulb cost or save you money. But if you get a store discount or have applications where CFLs are unsuitable (like cold/high humidity/heavy vibration/frequent on&off cycling), then buy now! As a rule of thumb, for every 60W incandescent you replace with one of these, figure it will save you $2 per year for every hour you typically burn it per day. If you have a 24/7/365 application, it will pay back even the $50 price in a single year. With reduced A/C use and bulb replacement costs, it should even turn a profit. Make sure you place these bulbs in the highest use rooms of your house so they have the quickest return on investment.
Durability
To take the L-Prize crown, this bulb was put through a slew of very rigorous tests FAR exceeding the requirements of Energy Star LEDs. The DoE put these LEDs, along with some high quality CFLs in a light bulb "torture chamber" where they were subjected to extreme heat and cold, high humidity, vibration, repeated on/off cycling, and various degradations of voltage and electrical quality. ALL the L-Prize bulbs emerged unscathed from the stress testing, while every single CFL died. I wouldn't worry too much about breaking the thing. Though pretty hefty, it has no fragile filament, no glass, and no moving parts. Teardowns of the bulb show it has exceptional build quality and use very good electronics and capacitors inside. Even so, save your receipt and UPC for the warranty period.
Life
Unlike the sudden death of traditional bulbs, LEDs fade over time and are normally deemed "dead" when they reach L70, or 70% of original light output. High heat accelerates the degradation. Well, the DoE has been running 200 of these bulbs continuously for over 12,000 hours at 113°F (45°C) in accelerated life testing to verify Philips' claim of 30,000 hours life. With 95% confidence they can predict that these bulbs will maintain over 99% of their light level after 25,000 hrs of use! Amazing!
Updates (Feb 2013)
LEDs are a rapidly evolving technology, and there have been notable changes in the past year. Here are a few:
- The L-Prize bulb formally received Energy Star certification on May 4, 2012.
- DoE testing is ongoing, still with no failures among the 202 test bulbs after 22,000 hours of use. Also, an L-Prize bulb will be housed in the Smithsonian next to Thomas Edison's original incandescents. It's that big a deal!
- Massachusetts and Rhode Island residents can buy these bulbs for just $10 each. That's a KILLER price. Google "estarlights" to find the website.
- Philips started selling packs of color-changing LED bulbs called "Hue", exclusively through Apple stores. Very pricey, and only 40-Watt equivalent brightness, but Forbes called it "The Best Product of 2012". I bet this will become a common feature for home lighting in several years.
- If you like the appearance of Hue, but can't pay $60 per bulb, Philips now sells
new 830-lumen, 11-Watt bulbs with the same (not yellow) aesthetic for $25. The 75 lm/W efficacy is midway between the
old AmbientLEDs and the L-Prize LEDs, but it can dim down to 2% of full brightness. They
also come in 5000K (daylight), if you prefer a bluer light.
- Switch Lighting released bulbs (in
40,
60,
75, and soon 100-W equivalents) they claim can safely be used in totally enclosed fixtures, unlike most other LED lamps.
- Several 100-Watt equivalent LEDs are entering the the market now, but they're usually in the longer A21 form factor. A year after launch, the L-Prize bulb remains the lamp with the highest efficiency and best color accuracy, as well as being the LED brightness champ in the typical A19 length. But expect that to change in 2013!