First, they are different things:
A Clone is an exact genetic replica of the plant that the clone is made from. It will always be the same sex, color, etc. A "tissue cultured clone" may simply be thought of as a microscopic cutting of an immature plant. A cutting off a mature plant can also be called a "clone" as it will also retain colors, shape and sex of the plant it was removed from.
A Seed Grown Plant may be the same or slightly different than the parent plants. Sometimes it could be very different maybe bigger than usual pitchers, darker color, lighter color, etc. in which case you may decide to designate it into a form or variety and start a new clone from your abberant plant. Seed grown plants can be either male or female, you will never know which until it matures in 5 years or so. With clones sometimes the sex is known and this is helpful if you are interested in breeding or otherwise producing Nepenthes seed.
Seed grown plants tend to grow much slower than clones. Likely this is due to the starting stages of the clone having ready access to nutrients and "easy living" conditions while invitro in the laboratory.
Basically if you're thinking of starting a program to develop Nepenthes hybrids it would probably be a good idea to start with 4 seed grown plants of each of the species you're interested in. This should give yourself a good chance of having males and females of each species. Females are said to be a rarity.
If you're like me and just wanna have a collection of awesome plants buy clones cos they make a more impressive plant faster.
That's the difference to me anyway!