WELCOME ABOARD!
The question to your question is, what are you looking for? Have you ever played a subsim before. If you're looking for a great gaming experience, then yes, in its current state SH5 is wonderful. The old negative reviews were because of problems. They have mostly been solved, and many people love the game.
The current negative reviews have nothing to do with the game, but rather with what it represents. Fans of the older sims dislike parts of SH5 because it doesn't represent what they see as a 'proper' submarine simulation. I'm one of them, but don't let that stop you. SH5 is well worth the price ($5 on Amazon), so even if you end up not liking it you won't really have lost anything.
But I think you'll be happy.