If you want to drink the best tea, you must have leaf tea. There's a huge variety of stuff called 'tea' out there, but only leaves that come from camellia chinensis can properly be called tea.
Herbal and flower brews, other brews made from water and leaves, e.g. Rooibus shrubs, aren't teas at all.
There are two basic methods of the first processing of teas, and the geographical areas with their particular soils and weather patterns, can result in teas with some variety of flavour. It's after the initial processing is done that processes are applied to the leaves that produce the many different flavours and characteristics of the famous and not so well known teas. Processes can include fermentation, smoking (originally done by burning camel dung!), mixing with flowers, other plants, perfumes, oils etc.
There's a lot of stuff on the web about tea production, and the grading of teas (what goes into tea bags being the lowest quality).
Search the Web for pages on tea production and grading, and you'll get an idea of the many crazy ideas people came up with to produce this stuff.
I've tried lots of teas, some of them really disgusting, and always come back to the same favourite tea - second flush Assam. It's a lovely tea, IMHO, strong and malty, naturally quite sweet to my taste, and doesn't seem to 'stew' if I leave it to brew for too long. The second flush leaves have a rounder, fuller flavour than the still very nice first flush.
Coffee can't compete with it. 