Jerry - I too have begun to look at both GedSite and TNG. Both look promising. I was just wondering if there were certain features/functionality that pushed you towards GedSite instead of TNG?
Initially, I just thought GedSite was much easier to deal with. It "basically" just makes static HTML pages (about which a bit more in a moment), and I already have a Web site hosted at godaddy.com that works just fine with GedSite's static HTML pages. I can easily transfer my RM data to GedSite via GEDCOM. GedSite makes the static HTML pages on your local hard drive from which you can burn them to a CD or publish them on the Web or whatever. As I said, I publish to my already existing site at godaddy, but GedSite supports a low cost publishing option of its own. You can use it or not, depending on your needs. You may not wish to publish anywhere online and instead you may wish just to burn the static HTML pages to CD to distribute to family members.
TNG instead stores your data as "data" instead of as HTML pages (you can load your data into TNG via GEDCOM or you can type it directly into TNG). Having stored your data, TNG then generates your HTML pages dynamically upon request. On it's face, the dynamic generation of the HTML pages is an advantage (and is strongly advertised that way by TNG). but I'm really just more comfortable with static HTML pages. And in particular, TNG has to run from a Web site, and the Web site has to support PHP (easy to do) and the Web site has to support MySQL (perhaps not so easy). Because of these requirements, you can't simply burn a TNG site to a CD and share it with a family member.
Another early consideration was that GedSite would import RM's sentence templates and use them when generating its static HTML. I never got as far as seeing how you controlled sentences with TNG. To be totally honest about it, in the bitter end I decided to set up my sentence templates in GedSite rather than importing them from RM. There were subtle nuances that worked better for me if I defined my sentence templates in GedSite. It appears that about 99.99% of RM users simply use their RM sentences in GedSite, so I'm an outlier. Your mileage may vary.
The final straw was that I could attach media images of documents (death certificates, census pages, whatever) to facts tor to citations or to both in RM and then GedSite could display such evidence in either or both places on the HTML pages generated by GedSite. For example (and this is a long term complaint of mine about RM because it can't do it), I could attach a photo of a headstone to a burial fact in RM and GedSite could display the photo along with the same burial fact on my HTML pages generated by GedSite. This is just so wonderful. I've been looking for years to put all my evidence front in center in my "reports" and GedSite makes it possible for HTML pages. I don't know whether TNG does this or not, but it works great for GedSite.
In its discussion of loading "data" vs. static HTML, the TNG Web site strongly supports loading the "data" as being much better. I equally strongly disagree but there are advantages and disadvantages either way. One concern with static HTML is that each person in GedSite gets their own "page" when you view the site. But GedSite is able to batch a large number of such "people pages" into a single HTML file. The default is 50 "people pages" per HTML file and the number is under your control as the author of your site. I have not found this to be problem at all. RM's old pre-RM6 Web pages generated static HTML. RM's newer RM6 style Web pages and MyRootsMagic Web page load "data" and generated the Web pages dynamically. I again think the static HTML approach is much better and I think that RM is kind of going in the wrong direction. I suspect I am in the minority with this view.