One of my past freelance clients (Company X) recently reached out to me to discuss a job offer for a full-time, salaried position. The real dilemma is that I just started a full-time job with a different company (Company Y) just a week before this conversation. I hadn't done any work with Company X for a little over a month and thought I had finished all of the work they needed, so I was caught completely off-guard by this. Frankly, it's out-of-character for me to even be considering their offer, because I've already made a commitment with Company Y and know it's not a good look to immediately bail.
But my work with Company X has been one of my favorite projects that I've done; I worked with them from their inception, have a great rapport with their small team (about 20), and a great working relationship with the CTO who has acted as a sort of mentor to me. (I'm very early in my dev career, and while I've got a grasp on front-end fundamentals and frameworks, he's set up one-on-one calls with me to 'teach' concepts otherwise well-outside my wheelhouse, and has solid understanding of and patience for what I do know and what I don't.) I feel particularly attached to their project, as I've been acting as the sole front-end dev and built their UI from the ground-up with free reign to use the methodologies and structures I prefer most. Plus, they're offering about $10k more than my position at Company Y.
Company Y is a much larger, more established company, but I'm not sure how I feel after my first week. There was no onboarding process, very little communication--I spent two days coding the pages that were assigned to me only to find after pushing them that they had already been assigned to and completed by someone else in our group of 6--and from what I've seen, the code looks a little 'dumbed-down' from what I normally write; there's not much reason or rhyme to the HTML structure and I'm not 'allowed' to work with CSS preprocessors as not everyone on the team knows how to use them. (The last bit is the most frustrating for me, as I consider myself someone who specializes in Sass and told them as much in multiple interviews.)
All else being equal, it should be easy for me to decide to just accept the offer from Company X. I feel proud of the work I've done with them. (Company Y is a financial group, I'm a hippie-dippie art school alum; our morals are oil and water.) But my biggest concern is this: Company X is a very fledgling startup company, and while they've landed some very large and high profile customers, if I'm completely honest, I'm not sure how much I believe in their longevity. Plus, because it's such a small team, I don't know how much room their is for vertical movement. The structure of Company Y has a clear path for growth and a much stronger sense of long-term job security. If I were further in my career and had more networking and experience to leverage, I would probably feel much more comfortable taking the risk working with a young start-up. As a fledgling 'career-changer,' it's been extremely difficult to land any sort of full-time gig and I'm terrified of ending up back on the job market with little professional development should Company X not make it.
tl;dr I have the opportunity to do work that I love with a team I've got great rapport and chemistry with, but seems very risky long-run. Is it in my best interest to just stick with lesser-responsibility work that I don't necessarily feel motivated by and a team that I so far have struggled just to connect with if it means stronger job security as a relatively new dev?