Office (Loose Leaf) Tea Solution

The differences in quality between teas is usually down to the manufacturer and the product line. As far as I can tell, there is no discernible difference between Twining's English Breakfast tea (for instance) in bags or loose leaf. They are the same leaves, presented differently.

However, and this is the important part, there is a difference in how they infuse. Because of the limitations of the tea bag, and the flow of the water through the leaves, a loose-leaf tea is usually infused more quickly, and possibly better. That is, you get more essence of tea from the leaves into the water. There are different bag designs (pyramid bags for example) which try to bridge some of this gap.

The advantage of the tea bags is that they are easier to work with, as you don't need to strain the leaves out of the water, you can just pick the bag up with your spoon.

There is a lovely essay by George Orwell about making "proper" tea. Some of it is a matter of taste, but his point about the infusion is spot on, in my opinion.

For some teas, the strainer does matter. For a particular variety of green tea that I was considering importing years ago, the producer recommended a certain type of fine mesh strainer for best results, as apparently the leaves were just the right shape to clog up the "standard" Kyuusu-style mesh strainer. (Kyuusu is a type of Japanese teapot with the handle on the side instead of opposite the spout).

With black tea, I found that those glass teapot strainers with the little slits in them worked fine, but were a pain to clean. For Japanese green teas, though, they were a disaster, as tea leaves got stuck in them and the infusion never got very complete, and the water refused to drain in a reasonable amount of time. As a result, I refuse to buy another glass teapot with those little slits, because they were too unreliable for anything but large leaf black teas or certain "fruit teas" (as they were called in Germany).

Korean style one-person tea cups with large holes in the strainer component work reasonably well for green tea (and are designed for green tea), but often require toothpicks or bamboo skewers to clean if tea gets stuck in the holes.

My favorite teapots mostly use the Japanese-style steel mesh, though I have had good luck for certain teas with built-in clay strainer holes if they brew small quantities of tea.