My thoughts, experiences, and feedback for March 5-6 PVP weekend...
First, thank you, Artillery folks, for letting me play your game at this stage. Overall, it was lots of fun, and I look forward to seeing how it develops moving forward! What follows is a roughly chronological account of my experiences this weekend. I'd be happy to expand on anything here if that would be helpful.
Install
Excited to install, but the MS VC++ installer just hung. I eventually canceled it. The Atlas installer's 'modify' and 'repair' didn't do much to help (didn't provide an option to attempt to reinstall it), and removing/reinstalling from scratch also didn't try again. The solution was to get a windows update and then grab the latest installer directly from Microsoft.
Client
The client looks nice and seems to work really well. It would be nice if we could access game options without launching a game, but I understand why that may be difficult. Resizing the client seems to just scale everything. There was a lot of great discussion going on, and I was hoping to resize the chat text box, but it's not a big deal.
Bots
Started my first bot game, excited! The confirm button for choosing a faction is in a weird place. I feel like an accidental double click could lock me into a role I didn't want.
First three bot games, played as Alder.
Bot Game 1 (5-10 minutes): Not very fun, mostly frustrating, because I was fumbling around trying to figure out what does what. In particular, I fell like a tool tip saying that you need a certain unit to cast spells was missing. I now understand that it's the same interface, regardless of which units you have selected, but the interface didn't tell me that.
Bot Game 2 (5 minutes): Much better, since I started to work on higher-level goals, but had to quit because my wife was calling me for dinner. 
Bot Game 3: First win. Bramblethorn pathing quite frustrating. I seemed to have a lot more green (scrap?) resources than necessary. Gold was always limiting. Anyway to macro that? Very easy to kill neutral camps by staying the right distance away. They would just flounder around if you find the sweet spot. I expected them to start healing, but they never did, so I was easily able to get some cheesy kills (tried this again later with Hydros, didn't work, which made Alder feel much stronger/easier to macro).
The bots seems to attack my towers with no hope of actually taking them down, and the towers seem to fully(?) heal back up over time. Since attacking the tower is a big risk, it seems like they should get some sort of reward, even if they fail. Can the tower be whittled down over time? I guess I'm not convinced on the balance with tower attacking risk.
It would be nice if I could set the ping key to be left-alt. That's what LOL uses, so it was hard to get used to moving my hand all the way to B, even if the (former) SC player in me laughs at that statement.
Bot Game 4 (Hydros): Swirly particle effects on my dudes. Debuffs? Can I see them somehow? Clicking things doesn't give much info (dynamic health amount, buffs/debuffs, etc.)
PvP
Starting PvP. Yessss!
Loading screen chat was super delayed.
PVP: game 1 (20 minutes, Alder): Way more fun than bots. Some graphical artifacts. Nothing game breaking, it was my teammate's units rather than mine. One of the players on the other team dropped immediately, so it wasn't very fair and we won easily. Can't chat while waiting for players to reconnect/timeout?
Game 2 (45 minutes, Alder): loading screen, when at 100%, hovering over portrait/name distorts the way '100%' is printed. Solo bot lane, the flying creeps killed my workers after a misguided attempt to kill them early. It seems to be difficult to get them to drop aggro. Solo bot was difficult because my opponent outranged me severely. This led to me just sitting in the bushes and trying to snipe him when he walked by, but otherwise neither of us could make much happen. Our team seemed to respond better to pings and worked together than theirs. We lost a few battles, but ultimately sandwiched them a few times to take most of the map. The last 5-10 minutes were a bit a stalemate and not very exciting.
Overall, the pace seemed to be feast-or-famine. Either a lot was going on, or it was a stalemate. There were a few in-betweens early on with gem skirmishes in the middle of the map , but mostly any gem gathering turned into mutually assured destruction.
Game 3 (30 minutes, Hydros): Marktillery on the other team, but he dropped about 2 minutes in and was replaced by a bot. Pacing was a little better, but still a few dead periods. The ~10 minute mark was the worst in terms of nothing to do, because my ally didn't want to help me clear the flying creeps. We were winning on the map, but the other team won by just bum rushing us with 4 juggernauts straight to the nexus and we couldn't stop them even though we got there in time...
Game 4 (30 minutes, Hydros again): The team fights were very fun. Mid game was nothing but Leviathan vs. Orion, with me forced to build Orions since Hydros doesn't have much AA. Teammate was able to freeze them, so the Orions wrecked them.
It ended like game 3 only we even more clearly dominated every team fight and again they just killed our base quickly with a few juggernauts before we could stop them. Very frustrating. We got to the base as they were attacking it, but they just had too much health. I feel like this was very cheesy and at least so far, don't have any real indication that it's coming.