Let's start our journey by looking at terms. Otherwise, we won't know what we're talking about, and chances are we'll talk past each other.
Tantra is an old religious teaching deeply rooted in ancient hinduism. It poses that the world of phenomena is a world of dualistic oppositions - black/white, male/female, active/passive, etc.; and that beyond those phenomena, there is absolute, unspeakable unity; every word we use to describe this unity is inherently wrong, because words, too, are phenomena and thus subject to dualism.
Tantra, now, aims to achieve a state of enlightenment - i.e., as it were, unity with this universal unity - by various means: meditation, breathing techniques, visualisations, mantras. One of those means lies in the acceptance and transcendenc of one's sexuality.
As far as I know, the "authentic" traditions of tantra put a lot of focus on asceticism. Which is probably not what one thinks of when one hears the word "tantra", but it does fit in well with the strong ascetic tradition inside hinduism.
It also used to be a highly secretive, esoteric system of stepwise initiations by a guru.
Somewhere along, or rather alongside, the "spiritual" re-awakening of the 1970s and -80s, the tantric teachings were imported into the western countries. Of course, the west in our times being what it is - far from "wild", but eager for money, and at the same time eager to fill the perceived spiritual vacuum that the eagerness for money brought with it, the teachings were sucked up, well... eagerly..., and at the same time were completely transformed.
Basically, what we did was that we stripped tantra of almost everything related to hinduism (except for a few words, which I will probably talk about in a later posting), specifically of the guru doctrine and the relations to the hindu pantheon, and on the other hand, we added a therapeutic slant to it.
While for the more spiritually-minded, a few "energetic" teachings were added.
The basic idea in all this was that a gentle touch can not only bring good feelings and strong orgasms, but also emotional healing, a better connection of body and mind, and whatever one sees as spiritual awakening.
Thus, neo-tantra was born: Adaptable to the needs of prostitutes and their customers (we shall have to talk about whether professional tantra is prostitution later on); but also appealing to the spiritually inclined esotericist, as well as the couple in their best years who would just like to rekindle the flames of their slowly burning-out sexuality. You can explore your intimacy in groups without ever running any risk of getting an ugly STD or (heavens forbid!) having to ouch another person's genitalia - or you can get a "tantric massage" with a slight smell of incense, a few candles and a very Happy Ending for your lingam, from your run-off-the-mill prostitute arond the corner.
Maybe this does sound a bit - shall we say "skeptical"? Well, it's probably not - at least not in the way you might expect.
You see, I happen to be convinced that pleasure in all forms is a good thing, as long as nobody gets hurt. And orgasms are probably one of the most intense forms of pleasure that we puny humans know. I also happen to think that roughly 95% of the male population haven't even begun to explore their full orgasmic potential (with women, it's probably different, I don't know - though my impression is that there's not a lot of difference there).
My experience has been that those intense tantric pleasures make me more peaceful, confident, balanced and energetic. So far, I haven't seen any bad side effects - that is, if we disregard the occasional sore PC muscles, the back pain from far too much lying on my back, and the blistered fingers (okay, just joking here...). All of which are, of course, very real dangers of the tantric practice, which I feel obliged to share with you, in case you meditate on walking down that path.
But apart from that, I simply cannot find anything even remotely bad in the idea of a practice that gives you almost instant ecstatic pleasures, while making you more aware of your physical sensations, getting you to lie calm for an hour or two - and all of that while you're own your own (completely free of charge) or with (a) partner(s) (free of charge if you find a willing partner). It gives me a tremendous sense of power to know that a little conscious breathing can make me feel better than I probably ever felt in my whole life. And the best thing is that nobody can take that away from me, except some serious brain damage or, obviously, death itself.
So, what AM I skeptical about?
Well, let's just say I find the religious overtones rather... misleading. I don't need to call my cock lingam just to feel more enlightened. In fact, I'm pretty sure that enlightenment in the strict sense of the word just doesn't exist. I find the idea of guruism and stepwise initiation based on the whims of another man's fancy disgusting - in fact, I think it's just a thinly veiled power game. (Please don't tell me I would have to know the hindu religion better to judge that - religious hierarchy is religious hierarchy and an abomination as such, whether it be the catholic clergy, tibetan lamaism or hindu gurudom.)
On a more general level, I'm really pissed off by the idea that only "authentic" tantra is valid, or that neo-tantra is somehow a watered-down, wishy-washy thing that does more harm than good. If you happen to be of this opinion: How on earth is it your business to decide what I like to do in order to feel good? How come you know better than myself what's best for me? If you want to make a point about spirituality, or why it's a bad idea to pay for sex, okay, make your point and let's talk about it. But please don't play the "authentic" card without ever having defined what you mean by "authentic", or why you think it's important. And also, please avoid words such as "superficial", "materialistic", or "western" as general terms of disagreement. These are overgeneralized, vague terms that don't actually convey any meaning, and thus my only reaction will be to kindly ask you to define what you mean.