Since this thread was necro'd anyways...
So, I actually just started a campaign with an Artificer Artillerist, and I have a few thoughts and notes.
Some background, we are starting at 5th level and running through "The Dungeon of the Mad Mage". I'm playing a Rock Gnome, and took the Healer Feat (though that was a tough call).
The Good
1) Arcane Firearm is really impressive. I don't think it has been too noticeable yet, but a 1d8 on all spells and cantrips is a sizable boost to my damage. Part of that might be that other than my cantrip I've used few damaging spells, but the one time I did it was an AOE and we only roll damage once for those. So that 1d8 applied to the entire group and was fairly devastating. But even without that, allowing me to average about 15 pts of damage a turn is keeping me in-line with all but our biggest damage dealer.
2) Protector Bot is life. Seriously, those Temp Hp are the reason we have not TPK'd yet. We are only two sessions in, but our DM is realizing a major problem. None of us sneak. We've pointed out, none of us can. Literally, we only have one person who does not have disadvantage due to their armor (the sorcerer) and none of us are more than moderate dex. So most fights start with us getting ambushed when we open the door. The only reason we are still up is because I've been able to dish out between 5 and 11 temp hp every single turn, usually hitting most of the party and I always prioritize the frontliners. For our next session I finally need to summon a new turret, and I'm going with the Cannon just to see how effective it is, but I can see using the Protector 99% of the time.
The Concerns (not problems, just things to watch out for when playing or running)
1) I think it is really important to pay attention to tools and probably the Xanathar's rules when you have an Artificer in the party. I know I got extras because of Rock Gnome and soldier, but I have 5 or 6 tool proficiencies when it was all said and done. It takes up a signifigant chunk of my character, and you have to respect that about an artificer when you get one in the party.
2) Melee is not your friend. This is partially a build choice, but despite my being quite decently armored I actually have almost no melee options. I got a dagger and that is the best I can do, and I spent my two cantrips on an attack and mending. Now, I could have taken a feat, gotten another cantrip, and had a melee option. I picked healer because I was planning on being supportive, so this is on me, but you do not get many good melee options at all, so if you don't leave a cantrip for that, you are going to be struggling hard if anyone corners you.
3) You are very limited on spells. Honestly, play a bit like a warlock. Rely on your at-will most of the time and only use those big spells when they are going to have an out-sized impact. Except for making those turrets because they will be mire useful than a 1st level slot, but you run out quick. 5th level, and I only had 2 level two spells. In fact, I've only used three daily resources at all. With one infusion on me for casting (+1 focus) and one to increase the defenses of an ally. If you are an artificer, you will likely be doing the same attack pattern again and again and again, because you have to.