there is always loss of quality. You can use the best setting in the world, but when you convert the dvd to a divx, you lose quality, when you convert from divx back to dvd, or in your case svcd, you lose quality. No big loss though, it's fine for your tv in most cases
time varies on computer. If look at my computer specs on my sig, it takes me about 2-5 hours to encode a dvd from divx depending on the setting i use (bitrate)