I was an Alpha Tester, a Beta Tester, and a Founder (pre-ordered it).
It was fun. I have many fond memories of playing with my friends who stuck with it from Alpha to Launch.
However, I felt it didn't live up to its creative potential.
I was always looking forward to building-related updates every month, but the primary focus was typical MMO activities (Smash X enemies, Collect Y items).
In the LEGO message boards I suggested brick building missions as an alternative to combat missions, but got negative feedback.
When I first read the Assembly Summoner could 'summon their creations', I was hyped. I thought I could use one of my custom builds to fight for me.
Instead, I could summon 3 different prefabricated creatures.
Speaking of which, the 4 factions made no sense to me. Imagine an MMO based on Hamburgers. Now, imagine there are 4 factions players can join: Hamburgers, Hotdogs, Tacos, and Ice Cream.
The factions (Assembly, Venture, Sentinels, Paradox) resulted in players wearing 12 specific outfits for convenience and petty arguments.
Looking back, it was a good game, but not the right game. They would've been more successful had they released LEGO Worlds back then instead.