I think that depends on what Penguin is offering you. I’m all about self-publishing because most traditional publishers aren’t going to help you much in the marketing department. I figure if you’re going to have to learn the business end of being an author either way, it makes more sense to publish with KDP because your royalties are higher: 70%.
I think in the long run, self-publishing is the way to go, but I don’t know the details of your deal with Penguin or what your advance looks like so please weigh the pros and cons of what Penguin is offering you.
I'd be happy to chat with you about it in more detail.
How much money do you have to spend on your release? Do you have skills in cover design, formatting, editing, proof reading, social media marketing, or promotion? Do you have connections with bloggers or reviewers, or understand what you'll have to do to grow a fanbase? How many books are you planning on releasing? How fast do you write? What genre are you in?
Self publishing is more than just hitting publish on a book. It's a lot of various skills that require a lot of time -- or money, if you want to hire it out to others. Having a professional team behind your book could be an absolute boon, and publishing through Penguin could give you a lot of respectability in certain circles.
I exclusively self publish right now, but I'd say only 10-20% of my time is spent publishing. The rest is handling all the marketing, promotion, graphic design, formatting, web design, etc. that self publishing requires.
If you are a self-published author, you may want to consider publishing via both options. I just remembered a survey I did with US-based readers when I published my book. I initially wanted them to just be on print versions to hold a special offering for the books.
However, 80% of the readers say they rarely read print books nowadays and most of them consider continuing the books via Kindle.
Though, one answer struck me the most.
One guy said, it's not up to us to decide the definition of "reading." It's up to your audience.
So, if you're thinking of publishing your book, it's better of have it either way because the end goal, aside from profit, is having your books read by your audience. Whether it's on kindle, android or live book, they should have the option to choose.