Here's my really long rant on my experience with SoS1 and 3oT, but a reply to the topic first...
Personally, 9/10 on Trio of Towns. I play the series more for its characters (+ the interaction) more than the farming aspect itself, hence I'm really biased towards how diverse and interesting the dialogue is in each game. I love the way more expansive dialogue over SoS1, and especially love the fact that every character has a "daily story" to tell (especially Inari)! The bachelorettes are interesting characters as well; I wasn't really keen on ANY of them (except Kasumi) when I watched the trailer, but as I played through my first year I couldn't help but love all of them <3. I wish there were like at least 3 bachelorettes in each town though.
I absolutely love the replay value in this game as well. So many recipes and clothing to collect, crops and animals having more properties to max out; and consequently, there's different classes of Animal/Harvest festivals now to balance this out. Speaking of the festivals themselves, the Animal/Harvest festivals pose quite a challenge for like, the first 3 seasons of the game, after which they pretty much pose no challenge and give you an auto-win as long as you submit maxed out animals/crops. After a while, they become more like a monthly chore than an actual exciting event to look forward to. As for the other festivals, I'm really glad to see every town have its own unique festivals (more events to join!), but really pissed that my spouse can't attend other towns' festivals and yet my child can. What's more annoying is that in the romantic festivals (Starlight/sealight festival) the respective bachelors whom I'm forced to go with practically rub it in ("oh, it's a shame Kasumi can't attend, let's go together instead"). Since the objective of the game is to bond the three towns together, why shouldn't we see more villagers from other towns start attending other towns' festivals as the Town Link Rank goes up? EDIT: And I just realised that I can't choose my child as the partner for the -light festivals, wat?
As for the farming side of the game, I feel that it took a turn for the worse compared to SoS1. The biggest gripe many, including myself, seem to have is the weird grid layout system as compared to the more liberal design from SoS1. It feels more like some annoying Professor Layton puzzle to fit all the field plots and power circles and barns/coops in proper layouts to not waste any space. It kills me that I can't put anything at all inside that large, wasted 3x3 grass space of a large barn/coop. In SoS1 you could set the fences around the barn and even plant grass within them for the cows to graze on! More gripes I have are that the default tools are too slow and consume too much stamina. Refilling the watering can every 4-5 fields is really irritating :< Speaking of which, you used to be able to move while watering, somehow they removed that in this game too. The improved factories are great - they take up only 1 space and you no longer have to walk inside to make stuff (though I admit the old SoS factories, while inconvenient, look way cooler). The new tool system is amazing too, except one thing - the stupid flashy animations once you upgrade them to a 5x5 area. They look cool, but actually slow down your work in some cases (you chop trees slower, hammer rocks slower, and mine wayyyyy slower thanks to the animation playing every single hit). The only tool worth getting 5x5 on is the watering can.
I'm rather disappointed that the house no longer can be customised freely, and that there's no more double-floor housing available. Though as a bonus, the new interior house designs look really amazing. The Music Club mansion has an inbuilt music player which I wish could be installed in all designs. The fridge being replaced by the storage box is really weird to me - I can't imagine this large box irl chucked full with fish, milk, eggs, vegetables together with weird animal necessities and jewels.
Not necessarily relevant to the topic - I've played SoS1 into Year 7 (stopped some time ago) and 3oT to Year 4 (still ongoing), and I'm really not looking forward to losing interest in continuing the game...