I have a definite bias towards traditional astrology but I'll try to be fair here. And I do believe that some modern techniques, like astrocartography, are genuinely useful. They work. There are also some good psychological astrologers on the board.
But if you are new, and you're able to read the older texts - read them first. Ancient and medieval, even early modern (Lilly, Morin) astrology has a coherent philosophical base that you won't find in modern astrology. And I've found it far superior for predictive work.
I also think it's vital to learn the old rulerships and to be able to read a chart without resorting to the newer-discovered planets and asteroids. One of the biggest mistakes I see in modern astrology is a minor Pluto aspect being seized upon to explain a problem, whilst a Sun-Saturn opposition on the ASC-DSC line goes ignored.
I don't even turn on the outer planets in my astrology programmes, haven't done for decades except when people have asked for chart printouts with them.
Most people who end up in trad astrology do it because of a dissatisfaction with modern - modern was all that was on offer until very recently. But a whole lot of people stay in modern and don't investigate traditional astrology at all. So it's up to you.
Modern texts are easier to read for most people. But modern sacrifices so much technique, it's not even talked about in modern books anymore, and adds extra planets and asteroids to try to fill in the gaps left by dignities, etc. Still, you'll be up and running quicker than you would be with traditional astrology. And modern astrologers don't feel they're missing anything.
Ultimately it's up to you. Look around the board, which is mostly modern (there are fewer than half a dozen trads here). See what you like.
Over at skyscript forum there are some really good archived discussions, and even now an occasional discussion that have more traditional bents.
If you want to go modern, the Dummies intro book isn't half bad just to get up and running with what a chart looks like, Charles EO Carter is definitely worth a read because he was sane and methodical, some of Liz Greene's stuff (the Saturn book) isn't half bad, either.
If you want to go trad, I'd start with Sahl's Introduction to the Science of the Judgement of the Stars (a/k/a The Five Books). It's a horary text and it's so very clear that I love it - it explains planets, signs, and placements in ways that are easy to remember and you see how it applies. It's still a go-to book for me. Ibn Ezra's Beginning of Wisdom/Book of Nativities and Revolutions are very good too, and if you take this up, there is a PDF floating around of his Book of Reasons, which is indispensable once you've been into astrology for a while.
There are arguments for both. And we live in a time when you get to read both, and jyotish (Indian astrology) if you like, before you decide which one or ones you want to devote your time to. That's pretty amazing right there.
Good luck whichever way you go.