I wondered about this. I played a few Early Access games, hunted a few bugs out and gave suggestions. It was fun for a few games, sometimes my suggestions even made it into updates, but for other games I wish I would have waited for it to be complete and enjoyed the final version of the product as my first experience of it.
Now what about Project Ukulele? Well first of all, I don't know if there'll be an Early Access version. My hopes are that there will not, because I'd be tempted to play it in order to help. But for such a game, I really think I'd prefer my first experience to be the complete game, and enjoy it in all its glory.
If there ever is a beta, I'm sorry Playtonic but I won't bug hunt for you this time. I wish all the best for the game, so it's hard not to help, but I hope that Playtonic will have enough funds to hire game testers instead. If there's an Early Access version, I will need a support group for people who want to resist the temptation of playing an unfinished product.