The complexity within life is overwhelming. Anecdotal evidence is voluminous. There are countless examples of highly efficient designs. Yet, evolution isn't pushing for perfection. There's nothing within the naturalistic theory of evolution to say that higher and higher efficiency is the goal or the end result. Better survival is the product of evolution, according to the traditional view, which isn't the entirely same thing as better efficiency. Yet, as mentioned in other posts, evolution slows down when the ecosystem reaches equilibrium and the niches are filled. Evolution clearly isn't constantly pushing for better and better efficiency. The primary goal of evolution seems to be to fill the niches within ecosystems. So, the fact that there are highly efficient designs in nature is astonishing if it all happened by accident, and you will often see evolutionists shocked at the complexity of various designs in nature.
Let's start at the very beginning, since that's a good place to begin. In Darwin's days, living cells were considered little more than lumps that could reproduce. Thus to believe that some primordial soup could have produced cells was not too much of an intellectual stretch. That was then. Now we know that most cells are incredibly complex (beyond current understanding) and contain the equivalent of factories with assembly lines, postal services, gatekeepers, powerhouses, libraries of data, finely crafted tools (proteins), quality assurance and control teams, and who knows what else. We're only beginning to understand the full complexity of cells. The idea of a primordial soup producing cells is now considered overly optimistic, as one can imagine. Now scientists believe there must have been intermediate life forms. (There are only two basic types of cells: eukaryote and prokaryote. Most of life is composed of the more complex eukaryote cells.) Currently, there is no known candidate for an intermediate type of cell that could have made the leap to modern, complex cells more likely. Scientists are stumped.
One has to wonder what happened to the intermediate types of cells . . . if they ever existed. Consider that there is always a food chain and less complex animals are always welcome in ecosystems. Viruses and bacteria, for instance, are thriving, even though they are relatively simple compared to animals. There is no known good reason why simpler reproducing life would need to have gone extinct. So, where is it?
So, on the basis of that alone, traditional evolution is in serious trouble. The leap from inorganic material to reproducing 'life' is monumental. For evolution to work as proposed by Darwin, reproducing components had to form without the aid of evolution. Just two types of cells are perfect for making all life forms, but those types of cells are incredibly complex and beautifully efficient. Many cells (both eukaryote and prokaryote) have what is called flagellum, which act much like motors that gives the cells the ability to move around. ATP synthase is an essential component within many cells that is key to energy creation. ATP synthase has great efficiency, using a ratchet-like mechanism and uses trapped water to increase its efficiency. It's finely tuned to be as efficient as possible, it would appear.
But all of that is the lowest level of life. Amazing efficiency also exists on the macroscopic scale as well. For instance, flying fish are found to have wings just as aerodynamic as some birds and they fly out of the water at just the right angle to maximize their flight times. The survival need for such efficiency is not apparent, so why would evolution produce it? Another example is the hummingbird’s tongue, which is surprisingly complex. Humpback whales have the ability to navigate for hundreds, if not thousands, of miles in a straight line without deviating more than 1 degree, and scientists don't even know how they do it. Many other examples could be used to show that animals have complex designs that are often highly efficient, far beyond what is necessary for survival. Naturalistic evolution doesn't provide a good answer to explain the emergence of these features. Only created evolution can explain it well.
We could also mention how that evolution throughout history seems to have acted intelligently and how built-in mechanisms seem to aid basic evolution. Something recently discovered called the epigenome could also have huge implications potentially for evolution and the complexity of the mechanisms behind it. Logically, a random process of evolution shouldn't become refined and more and more efficient. Evolution has no ability or reason to upgrade itself. The efficiency of adaptations is astounding. How did it get so good? Randomly? If you can believe that, then you have a lot of faith.
Finally, evolution produces nice-but-not-necessary features, like eyebrows, eyelashes, fingerprints (on humans and koalas), animal whiskers, tails, and the appendix (not a vestigial organ like some textbooks falsely claim), to name a few of many. Evolution is finely tuned to keep minorly beneficial features and to eventually remove useless ones. It seems highly unlikely that a random process could pick and choose features so well. Notice, though, that existing animals rarely have perfectly useless body parts. If evolution is doing an endless experiment in improving the survivability of animals, then there should be countless examples of useless body parts that are evolving to become highly useful. Fingerprints and eyebrows aren't evolving to become highly useful; they do their job well, and we know precisely what they are and why they are there. Does any of this fit the picture of random evolutionary processes? To me, personally, it shouts design by an intelligent Mind. The evidence is not there to suggest a haphazard process of clumsy evolution. Evolution is smart, efficient, and designed.