Their (real) contrast ratios and viewing angles are much worse than those of IPS (In-plane switching) monitors. The color palette and consequently color accuracy is not as good either. Compared with the 8-bit H-IPS/S-IPS panels, TN panels are only 6-bit, which means that they can't produce as many colors, but have to emulate their palette.
The only upside to having a monitor with a TN panel is that their response times are lower on average. A lower response time means a lesser risk of experiencing motion blur and tearing of a fast-moving image on the screen, which is important for games. However, this is also starting to change as IPS panels mature and response times become better. The latest IPS monitors have greatly improved response time over previous generations.
There's also the matter of the price tag of course; a brand new IPS monitor is a lot more expensive compared to a TN-based computer monitor of similar size. For professionals (and amateurs) who work with photography or graphic design the choice is easy, but for the average home user it is harder to say if the improved picture quality is worth the higher cost.
S-IPS or H-IPS?
There are several different versions of IPS technology. S-IPS and H-IPS LCD displays are the most common right now. The different is not huge, but the short version is that H-IPS panels are newer and provide some improvements over S-IPS. Nonetheless, both H-IPS and S-IPS panels offer considerably better quality than TN panels.
The main difference is that an H-IPS panel has a different pixel orientation than its S-IPS counterpart. The electrode patterns in an H-IPS panel are closely spaced and resemble vertical lines, while S-IPS pixels are slightly curved when viewed up close. This translates to differences in contrast ratio and aperture size.
Because of the different pixel orientation, H-IPS monitors usually offer a higher contrast ratio compared to S-IPS. Another benefit is that distortion is reduced when the user views the screen from a sharp angle. The only downside to H-IPS vs. S-IPS is that the image could become too anti-aliased, or too smooth. High viewing angles of up to 178 degrees, on the other hand, is an advantage present in both variants.
Even though S-IPS and H-IPS monitors are slightly different, both technologies offer major advantages over monitors with TN panels. They are definitely a much better option for professional users who need high color accuracy. Of course, the advantage of improved picture quality is obvious to all users, and some manufacturers are starting to target home users as well.
Hopefully, increased mass production of IPS panels will lead to lower prices, and eliminate the need to compromise between quality and cost in the long run.
Source: ezinearticles.com