I am just curious about what is the comparison of value between them , as you think in the current market?
5N.com
4N.com
5N.net
4N.net
3N.net
5N.org
4N.org
3N.org
your opinion is appreciated
5N.com = I like them, about 90% are registered, about 50% are developed sites, 5% Chinese sites some of which are highly ranked in Alexa. They are good for traffic, zip codes (US and foreign), Chinese sites, and other uses. However, they just went through a buyout last year that fell apart, so I don't see interest spiking again until Chinese internet penetration increases such that prices for these rise more. Right now a random 5N.com is worth reg fee or less.
5N.net = see above, these aren't going anywhere until 5N.com's do. Marchex used to direct all of its zip code domains to the .net (why? who knows) but they stopped that. They still own about 50% of the remaining .net's, but unless you have a really good number, like a great zip code or 55599.net or something, your domain is not going to be worth much of anything.
4N.net and 3N.net = these are good domains that are worth considerably less than their .com versions but still command decent prices (I think around $20-$60 for random 4N.net's) and the Chinese do use the .net so that helps.
5N. org, 4N.org, and 3N.org = A big warning on the .org for numerics: the Chinese do not really use .org so the big driver of prices for numerics is not there for .org's. That said, if you have a really good .org, like 90210.org or something, it should be worth something. NNNN.org's are about 90% registered I think, and 3N.org's are worth a decent amount depending on the number. I just don't recommend you invest your money in this area unless you have a particular development plan, since your domain is not going to get traffic as most numeric traffic is from China anyways.