Vinh
I am interested in your experience. Here is some of mine.
The longest I kept a division of the same orchids in water culture now is between 4-5 years. As far as doing this for personal reasons for me, Here is the first two for preferring water culture long-term. One is to keep a large plant compact by frequent division when not in bloom since the roots are growing dense and short, as you can see from the close-up picture of my post on Sharry Baby below, and the plant remains easy to lift. A large pot of lecca can be very heavy to lift. Another one is that division is much easier, and if the plant really likes water culture and grows very fast, I can keep a much smaller, more compact divisions without interfering with frequent blooming, pot up the divisions I want to give away in S/H in a matter of minutes, on demand.
Onc. Sharry Baby in water culture
However, S/H requires much less attention than water culture, I can leave them unattended for more than a week, once they have established good roots as you can see in this post..
http://www.orchidboard.com/community...ome-alone.html
Some thoughts on my varied experiences.
I will try to make a quick 2 way division Water culture vs. S/H, 1. same or better in water culture, 2. better in S/H
1. would be some Oncidiums , like Sharry Baby and similar hybrids, All Bl. Richard Mueller hybrids I tried, like Bl. Sunset Glory, some Lc hybrids, such as Bl. Mari's Glory, Potinara type Catt. alliance hybrids, various dendrobium hybrids, Rodriguezia venusta, Angraecum leonis, and compactum, Howeara Lavaburst, Leptotes bicolor.
2. Catt. hybrids close to their C. walkeriana ancestry, brassavola species and pure brassavola hybrids, Darwinara charm, Oncid hybrids with heavy onostum, flexuosum and other fibrous or climbing rhizomed types in their heritage or these species themselves.