First of all, let me get this out of the way: if common shoujo tropes annoy you - cutesy blushing, sparkles in the background and fluff (along with a mild case of reverse harem and lots of pretty boys) - then this is probably not going to be the manga for you. It is very much a shoujo manga.
That being said, if you're looking for a lighthearted fantasy romance, then I highly recommend this manga.
The art is quite good, even from the beginning, and gets better and more complex over time. The poses are occasionally a little stiff but for the most part everything is proportional and beautifully drawn, and there's really nothing I can legitimately complain about. It's professional and often stunningly gorgeous. The character designs (especially for gods and yokai) can be quite creative. Those of the recurring male cast are likely a major draw for the female audience.
As for the characters themselves, although they're not all horribly original as far as personalities - the female lead is the typical high-spirited, headstrong, impulsive teenage girl, and the male lead is an overprotective tsundere - they're quite well-rounded and well-written. The side characters are given personalities as well rather than being left to fill typical cliches. Characterization is consistent and believable, and when it changes it's always for a plot-related reason rather than poor writing. I can only imagine the characters being a problem for someone who found the archetypes themselves frustrating; though they're played straight, they're not played poorly or flatly, and there's a decent number of dynamic characters who change over the course of the series. Nanami, the main character, goes from damsel-in-distress to able to fend for herself in a realistic progression, rather than relying more on the other far more powerful characters for everything. There does seem to be a preponderance of pretty, charming guys, but remember folks, shoujo manga. It comes with the territory.
The plot begins with an interesting premise and carries it through quite well in an excellently-paced manner, especially for such a long manga. The premise is below as a spoiler, but it only explains the general ideas set up by the first few chapters.
Nanami, an ordinary high-school girl, ends up as a land god after losing her home and her no-good father who ran away. Thus begins her task of dealing with various problems involved that come up in both being a land god and a high-school girl - more of the former than the latter. Another set of problems includes the fact that her fox-eared familiar, Tomoe, is almost an almost overpowered, gorgeous guy who is absolutely devoted to her service (albeit reluctantly at first). Nanami is human enough to... notice.
If there's one weakness with the plot, it's that it's held together in its overarching themes more by the romance than by the fantastical aspects. A person inclined to ignore the somewhat repetitive romantic back and forth might find the story arcs a bit episodic in nature. I believe that it is possible to read this manga solely for the fantasy aspect and enjoy it, but it roots itself firmly in its romantic plot as the factor of the series that carries it from storyline to storyline. Given that the development of the romance is quite gradual, this could be frustrating for a slow reader who gets annoyed at the constant romantic tension. That being said, both the comedic elements and the fantastic elements are beautifully done, and each story arc is well-built, well-paced and generally satisfying and thrilling for me as a lover of fantasy with strange monsters, otherworldly places and occasional well-drawn fight scenes. One might also complain about plot holes, but be aware that these tend to be Chekhov's guns in disguise rather than legitimate oversights.
By the way, this isn't to say that the romance isn't well done! In my opinion, it's more believable due to its length, and for fans of the blushing cheeks and fluffy cuteness it still manages to serve up a good number of doses even early on. As I said, it can get superficially repetitive, but there is genuine development for those who look closely. Spoilers below regarding further info.
Will they or won't they? They will. Oh how they will. The series is simply delaying the development until it can be the satisfying payoff to the biggest, best storyline of the series that it had been building to for a while. Besides, thanks to Tomoe's lack of a sense of personal space, the fact that Nanami figures out that she likes him fairly early on, the fact that the familiar contract is sealed by a kiss, and Tomoe's loyalty and overprotectiveness frequently sounding suspiciously romantic, the gods of shoujo saw fit to bestow enough fluff to keep the fangirls occupied until they finally do get together. This is one of those stories that includes a lot of "Aww look they really do love each other."
All of the above is what I'd say about the majority of the series, but a special mention should go to the time-travel arc. It's easily the best arc of the series by far, and with the rest being quite good that's saying a lot. It's everything about romance and fantasy that I could ever ask for, and I'm not even that much of a romance fan - but it goes into the territory of incredibly epic and completely solidified my opinion of the series as amazing. I spent a good amount of time ranting to my poor, unsuspecting, uninterested friends about it, which is not something I normally do. Seriously, if you only read this in order to get to the time-travel arc and then stop, DO IT.
Although I'm seeing people complain about the series going downhill after that, I feel as though it's just that hard to follow up. Plus, I have a theory that after using so much of the series to build up to the time travel arc, the author's trying to get momentum behind a slow build to another epic story arc and is simply taking her sweet time about it like she did before. I think there's been a shift away from the romance as the driving force of the series with more of an emphasis on an actual major villain, which caused a major shift in tone. If it's developed as well as the romance was then I don't foresee this being a problem once the manga has enough chapters to get the new plot off the ground.
I gave this manga a 9 out of 10, mainly because it's a not-for-everyone story. You have to like fluffy romance and a major appeal to the female demographic to really enjoy it. However, it would certainly be my recommendation for fans of shoujo manga who want their romance with a large side of gods and demons and a sprinkling of well-placed comedy. Whatever you do, I definitely recommend sticking with it until the time travel arc - despite the amount of time it takes to get there, it's worth the read just for that.