ad_hoc
(they/them)
Just my personal opinion as an Eberron DM in a 5e campaign, and having played and DMed 5e since release, but Artificer is pretty ridiculous. At 10th level, they can attune up to 4 items, at 14th level, 5 items (ignoring requirements, by the way), and at 18th level, 6 items can be attuned. Attunement is a huge balance equalizer in 5e...honestly surprised the designers allowed this. On the other hand, many of their infusions, which are Artificer-created permanent magic items, require Attunement.
Funny thing you can do: infuse an item, have your high-Charisma Deception-proficient friend sell it to a shop keeper or other buyer, then walk away. Shop Keeper can Identify it via normal means (spell or short rest), and see that it appears to be a normal item. Then, infuse an item over your Infused Item limit, expiring the oldest infusion you just sold, leaving the buyer with a mundane item.
Otherwise, great book from what I read so far and nice to see it updated for 5e.
That depends largely on your style of play.
I have never seen anyone hit the limit. We use the treasure hoards system from the DMG. The party might have 1 attunement item per character by mid to high levels.
The Artificer may change that of course, but until I see it in play that seems okay.
I don't care about Eberron so I voted based on how I like the Artificer.
Seems mostly well designed on paper. Unfortunately I don't like the Alchemist which is my favourite theme. The Artillerist and the pet one seem fun though and I have good minis for both so I could see them ending up in play and being a fun addition to a party.