How is it compared to 5e? I would like to try it, but I'm afraid my players wouldn't like it that much, since they adore the high octane D&D combats, and crazy ass player high-magic abilities.
I mostly concur with what
@TheSword wrote, but eventually magic gets very powerful. With the right rolls it can be much more powerful than magic in D&D. But magic is risky. Things can go wrong and you can suffer miscasts and corruption. A couple warnings:
First, many players may be frustrated with magic run using rules from the core book. If you have players that really want to play magic users, I highly recommend getting The Winds of Magic. The alternate rules for casting are, IMO, are much better than the core rules.
Second, one legitimate complaint some people have with the rules of magic is that there can be a bit of trap for players are new and don't fully understand how different skills and talents affect casting effectiveness. If the player min-maxes a bit, casting can be much more reliable, much more quickly. Players who don't realize this until later in the game may have complaints similar to complaints some have with D&D 3.5 or Pathfinder 1e, where they feel they feel into a trap due to lack of system knowledge. There are many fans of Warhammer who just buy into the deadliness and chaos baked into the game. But for new players, esp. coming from D&D, you might want to mitigate it. E.g., have them pick race, class, etc. They won't get the starting-xp bonus from randomizing character creation but many D&D players want to build a character concept so don't force them to randomize it.
You may recommend that a player wanting to play a Wizard play an Elf to avoid physical mutations from exposure to chaos influence. Also, instead of trying to level up their career, spend more time at lower careers maxing out certain attribute and talents. You will not be able to increase certain talents after you go to the next career level (at least without extra cost in XP and coin through a downtime endeavor). Magic users will want to put their XP into maxing out the Instinctive Dictation and Aetheric Attunement talents when they get access to them. Also increase intelligence and will power early on. Also using the rules for familiars in Winds of Magic, a Power Familiar with its Magical Assistant talent helps. By the second career level, when they get their staff and robes, that will help as well (using the rules in Winds of Magic). Wizards will still not feel very magic in the first level of their career, but they can increase the likelihood of success when casting magic and get much more powerful result sooner by focusing on spending EXP on the attributes and talents discussed above.
One of my players loves to play wizards in D&D and has played wizard characters (well, and one sorcerer) over the past 10 years of my D&D campaigns. He is enjoying the magic rules in WFRP (with the Winds of Magic book). But it does take more time in WFRP for a wizard to have a lot of spells to cast.
As for combat, we a much preferring it of D&D 5e combat. I will say, however, that using Foundry improves the experience. There are a lot of time you need next to roll on random tables during combat. Because that is automated in foundry is happens instantly so you get the benefits of more flavorful, dangerous, and an fun combat they bring, without page flipping. The advantage mechanic also makes combat far more dynamic. I prefer the Group Advantage rules in Up in Arms, but the Core rules are fun as well. I just prefer how Group Advantage keeps the players thinking as a group in combat and having more reason to pay attention during other player's turns.
