I’ve already played Half-Life: Alyx long enough to answer your question. It’s one of the best VR games out there. I’ve been playing on Easy, since my reflexes aren’t what they used to be. There’s an even easier Story mode, which lets you experience the game in a less demanding way.
Have you played any of the previous HL games? If so, HL:A will feel familiar. There are numerous physical puzzles, like “What do I need to do, to get over there?” If you get stuck, there are many walk-throughs on the internet which can help.
HL:A is a slow-paced game much of the time; it encourages detailed exploration of the rich surroundings. It’s the first “true” AAA VR title (and that’s not just my opinion, many others have said so).
It certainly has fast-paced areas and it can be scary and unsettling at times, just like the original HL games. It’s a familiar world (to me) and it stays true to the previous games, while expanding the world into VR.
I think it’s a game which nearly every VR player should play (and will enjoy), since it lets you experience what a “next level” VR game can be. I highly recommend it.
HL:A is free, if you buy a pair of Index controllers ($300), which I also recommend. HL:A makes good use of those controllers and I think it helps with the immersion. Standard controllers are also supported (but I haven’t tried them, since I don’t own any).
If the price of the game ($60) is too high for your budget, I suggest placing it in your Steam wish list and you’ll get an email the next time it goes on sale (probably near the end of the year). Honestly, I think it’s worth the full price; I paid $300 for the game and got a free pair of Index controllers. I don’t regret the purchase.
TL;DR: Buy it. It’s a great game!