I think dry yeast is great for a lot of reasons. It’s easy to use, inexpensive, fairly versatile, easy to store, and dependable. The yeast are typically in optimal health as they’re prepared for dry storage. It’s hard to go wrong with dry yeast (although there are still some strains that I’d personally shy away from).
I think the major benefit of liquid yeast is that there are so many style-specific strains. Also, you can harvest yeast slurry and save it for future batches, as long as your sanitation is up to par. Of course, you could pitch a dry strain and then save the slurry from that, if you like a certain dry strain.
I like to keep a yeast bank of slurry because there are certain strains that I use a lot, and it’s a big savings. I built a stir plate and can easily grow a starter to any size I want, which is a great option too. That said, I think there are some people who use dry yeast exclusively.
As for your Irish Red question, you could give WY1084 Irish Ale a try, or the White Labs equivalent. If you’re looking to start doing some yeast harvesting and repitching, I’d give WY1450 (Denny’s Favorite) a try. It really does accentuate the malt character and body of a beer.