I prepared proportional amounts of Da Yu Lin tea in a gaiwan and a mixed clay teapot today. The gaiwan with a lower capacity has less oolong tea apportioned into it to level the playing field. Took a few small sips from each cup and made comparisons. With the lighter coloured infusion on the left, I could pick up fruity yet faint floral notes. The brew consequently was lighter on the palates and the tea coasted my tongue very loosely like margarine. In the second cup of tea, the basic notes found in the first cup were magnified many times and coated my tongue very densely like butter. I could pick up the changes in fragrances and track them more accurately in my memory. The differences are in some ways similar to eating instant chicken soup mix compared to slow-cooked chicken soup.
To try and achieve a sort of 'slow-cooked chicken soup' experience in the gaiwan, I dropped a few extra balls of oolong into it and proceeded with the second brewing session. This time the colour of the infusion from the gaiwan drew closer to that from the teapot but the brew felt colder due to superior heat retention properties of clay as opposed to porcelain.
The convenience of exchanging many different teas using a porcelain gaiwan has made it very popular with testing teas and narrowing down one's selection. With a clay teapot, we can test it out with a narrower selection of teas but must finally use only one kind of tea for brewing. In other words, the gaiwan and clay teapot complement each other in scoping for the best teas and eventually brewing these teas in dedicated teaware.
Editorial note: I left the teas to steep in the gaiwan and teapot overnight and found a more balanced brew from the pot with its freshness retained. Infusion from the gaiwan became more concentrated but had a rather prominent astringent note that lasted for about 20 seconds. The freshness of this medium-grade Da Yu Lin tea was not there anymore in the gaiwan despite the more intense flavours and this led me to conclude that teapots in general have a more air-tight construction than gaiwans and their clays are more flattering on the performance of teas, i.e. teas taste rounder, more balanced and can even develop a longer aftertaste as a result of its interaction with the clay's porous quality.