We haven't played Shadows on the Long Road yet (and I don't know if/when we will fit it into the campaign) so this is based on Temple of the Nightbringers and Terror of Triboar only. However, the site doesn't let me comment on the component adventures, only the collection - I don't know if this is fixable?
Temple was specifically recommended to me as a good adventure for first-time players. It worked pretty well, but as someone with more experience of D&D the first part seemed a little railroady. More details on Melton would also be appreciated. However, it gets much better. The Temple is well-designed with real character. The encounters are appropriate for first-level characters, which is tricky to do, and the whole thing requires minimal preparation by the DM (which is always handy!). Crucially, there are non-violent solutions to many encounters, which is a very important concept to reinforce for new players. I did feel that the characters should have slightly more chance to find out a bit more backstory about the mask of Shar, and it's a dangerous item to give to a starting party since, as written, it gradually changes the user's alignment (which is something an experienced player might be happy to roleplay, but a new player not so much). There are a couple of slightly odd aspects to the temple layout - for example, the goblins are apparently terrified of the zombie library and yet they keep using the room next door as a dormitory, rather than moving into the empty storeroom on the other side of the dungeon? - but this is a great way to spend a session, and a nice opener for new players.
Terror at Triboar is also pretty good. There are plenty of details given of Triboar citizens and places which you can run with, and it's not an enforced linear plot. We're just finishing this up so I can't comment on the final battle yet, but my group liked this one even better. That may be because it gave me more opportunities to improvise, though, so I don't know whether a relatively new DM would feel the same way about it.
It's worth mentioning in the adventure description that Triboar is (potentially) a major focus of Storm King's Thunder, and maybe mentioning how it could link in to Phandelver and Princes of the Apocalypse too since it's in the right region. Also worth mentioning that this adventure interacts well with "Triboar - a Storm King's Thunder DM's resource" (http://www.dmsguild.com/product/197109/Triboar--a-Storm-Kings-Thunder-DMs-resource).