Disadvantages (Vinyl)

There are several risks and disadvantages to vinyl, compared to other (digital) audio technologies.

Vinyl is harder to maintain than CDs, and should ideally be stored in temperature- and humidity-controlled environments. (However, air conditioning, perhaps with a dehumidifier, is almost always sufficient.) Mold can grow on vinyl and may permamently damage it and its sleeve, and can spread from record to record.
Vinyl is very easy to damage during playback. Any scraping of the surface can permanently compromise the sound quality.
Surface noise, while often inaudible, will always be present and measurable, even on a brand new LP.
The sound quality of a record cannot be determined until you play it, increasing the risk of the purchase. Even brand new, sealed LPs can have significant pressing and warping problems that may make it unusable for listening purposes.
Certain parameters of vinyl recording and playback - notably, the vertical tracking angle (VTA) and the stylus rake angle (SRA) - were never formally standardized, and vary considerably between records. Distortion from these effects is generally considered extremely audible and very difficult (if not impossible) to correct.
Turntables and cartridges require periodic maintenance and alignment by a professional, usually a repairman or a dealer. Otherwise you must learn how to tune a system by hand, which may require a great deal of time to perfect. Maintenance may be necessary anytime a turntable is moved or reconfigured.
Any play of a record, even one, has the risk of permanently damaging the record. Repeated playback with an excessively worn or misaligned cartridge will cause permanent damage.
Vinyl playback is not nearly as portable as other technologies. Portable record players exist, but they are considered of inferior sound quality and require a motionless playing surface.
Investing in a high quality vinyl system is hundreds to thousands of dollars more expensive than investing in a high quality digital audio system.
Vinyl equipment reviews are notoriously biased and subjective, and it is extremely difficult to locate objective information about playback and build quality. Expect to purchase hundreds or thousands of dollars worth of equipment or features that you may not need.
Cartridge stylii wear out over time (typically 200-1000 hours) and require periodic replacement. High quality cartridges generally cost between $60-$6000. At the upper end of cartridge cost, playing a single LP may cost $1 in stylus wear alone.
Records are large and heavy. Transporting them correctly is logistically difficult.
The "book value" of many LPs, representing both its collector's value and its musical value, is often quite high - anywhere from $10-$20 for either new or used LPs to over a hundred dollars for collectible LPs.
LPs in general are neither overvalued nor undervalued. While they do not risk becoming worthless, they usually do not carry their value well unless certain releases become more collectible. Vinyl is not a particularly safe investment for collection or financial purposes only.
While there is some appeal in listening to older music in the format it was released under, that does not necessarily mean that one is any "closer" to the music than listening to it in a different format. Put more simply, vinyl is simply not any more of an "authentic" format than CD or MP3 by any rational measure; all evidence to the contrary is based purely on emotional arguments.
Financially, any benefits of the cheaper media must be compared against the amortized cost of the equipment needed to play and maintain it. Unless great care is taken in a vinyl investment, the cost can quickly outweigh the benefits.