I have been meditating for about 12 years, on and off. I'm not sure about the benefits. I think I may have received benefits, but its not something I can point to with words. Things can be subtle but still very powerful. Maybe I'm more relaxed, maybe I'm more patient, more grounded, more content, more able to take time to smell the roses. It's hard to say.
It's important to see what our condition is. I believe that all us modern folks are actually weird and dysfunctional versions of humanity. Most spiritual paths have a way of talking about this and the usual idea is that we each have two selves, one that is essential and exists in the moment, and one that is conditioned and focused on past/future and grasp/avoid.
Meditation is a chance for your essential self to get its time in the light, so to speak. But when we are in the present we don't care about benefits. And being concerned about benefits keeps us from being in the present moment.
So rather than benefits, think of meditation as a chance to practice being, or to just be.
If meditation has one obvious benefit, its that it helps us see how our mind works, and what we're really thinking about. And where our attention usually is (which ain't the present moment). As my (then) teenage son said to me after his first meditation class "Dad, I can't stop thinking!". So one of the benefits is seeing what going on inside yourself, learning about yourself. You'd be surprised at the misconceptions we have about what goes on in our own minds.
Some people meditate to have blissful experiences, or become more peaceful, or to calm down. That's fine, but when you have a idea like that, your setting a goal, having expectations, judging and rejecting anything that doesn't seem to be giving you the experience you want. But being in the moment requires that you accept the moment for what it is, not what you want it to be. Its hard because its so simple.
Even sitting cross legged on a cushion can be a trap, as I think of myself as "meditating" and being "spiritual". Better to meditate by just sitting in a chair alone in a room for half an hour and doing nothing.
I think the only thing to try to do, when your thinking mind will let you remember, is to place your attention on some sensation, be it a sound, a visual detail, or the feeling of space around you in the room. This is "doing" yes, but it then allows you to have a few moments perhaps of "being", and surely it is a good thing to just "be" fully in our life once and a while.