Like others said "best" is such an unquantifiable term. Best will really be what you like the most. What you like the most will be what fits your needs and preferences the most. In those terms, for me, a Lifereef is indeed the best (I expect I'd be every bit as happy with an MTC, but those aren't as common, same design philosophy). The two things that are so attractive to me about the Lifereef are the same things that have been mentioned before.
Pump and cleaning.
You can use any impeller pump that moves water in the venturi's appropriate range. You can use as cheap or as expensive of a pump as you desire. You can even put said pump anywhere you want as well. My skimmer pump is several feet away from the skimmer. On the opposite end of the sump. It wouldn't fit in my skimmer chamber, so it's next to the return pump. I like how modular the pieces are which allow you to configure it to whatever best suits your needs. It's not a reasonable assumption that pinwheel pumps from reputable skimmers will all break in short order, leaving you with a costly replacement. But...the fact that you can upsize your skimmer, or downsize it, change its footprint, and even keep it running for decades with minimal cost involved in any of those scenarios makes it an attractive option.
Secondly. Cleaning. Some of you may not mind. Some of you may have certain measures in place to keep a skimmer clean on its own. But...The past three needlewheel skimmers ive owned have required me to remove them entirely, disassemble, vinegar soak (ideally), take apart everythting and scrub clean, and reassemble and install. I havent had problems with skimmer adjustment or pump breaks, but the frequency of cleaning became tiresome. I hated having to remove and disassemble my entire skimmer every 2-3 months to keep it functioning. The needlewheels would get clogged with bubble algae and molts. Sediment would begin to build up inside the skimmer body and clog the bubble plate, ect. It would take me an hour or more at a time to clean it. Generally a very unpleasant task.
The lifereef doesnt really have that problem. If you want to clean your pumps impeller you dont necessarily even need to remove it from the tank to do so. A quick unscrew, and scrub with a toothbrush and back in it goes. The flow is so turbulent in the body you dont have anything to clog, or sediment to build up, and as others have mentioned, due to the nature of the foam head and how it is produced, you dont experince that stall in skimming when the neck gets dirty, it just keeps running same as it would when clean. If you happen to notice a dip in flow/air, simply unscrewing the venturi cap and running a pipe cleaner brush through it for a couple scrubs does the trick to disloge any buildup. The maintenance involved is so little that is a massive plus for me.
Does the skimmate look or smell any different than my eshopps or bubble magus produced? No, not really. I do get more out of it since it doesnt stall when the neck gets dirty, but otherwise I feel like it produces comparable skimmate. It isn't as energy efficient. My bubble magus used something like 16 watts grand total, whereas the lifereef uses about 100 watts, and adds some heat to the system, requiring me to run my cooling fans 24/7. So yes...there are SOME setbacks to them. No product on the market will be without some flaws as compared to another. But the things that matter most to me in a skimmer have been addressed which is why I am a lifetime customer of theirs at this point. For skimmers anyway....Yeah their sumps and calcium reactors are beautiful, but at their price point, they're not out-doing cheaper options nearly enough to take that plunge
