Summary: Blaster-line guns are decent but not extremely powerful or fun. Alchemers are weak when used by novices, but very strong and interesting when used by experts. So blasters will get the job done, but I strongly favor alchemers.
Blasters always deliver a decent amount of damage and knockback. There is no status. The charge attack is a bigger version of the regular attack --- not any more interesting. They are dependable but rather boring.
Alchemers have no knockback but offer several statuses. Really they are interesting because of the ricochets. If you aim correctly, you can often get the ricochets to hit the shot's original target, greatly increasing the damage output of the gun. Novice users, who can't land the ricochets, often find that alchemers do less damage than competing guns such as blasters and antiguas. But expert players can get much more damage out of them. So they have a learning curve that rewards skillful play. The top end of the learning curve is the switching technique. It can be used on many weapons, but it's famously effective on alchemers. The charge attacks are also very powerful, with many more ricochets.
Arcana is easier to handle. It's just a run of the mill weapon, but it can do above-average damage if used well.
It's charge shot offers better knockback to the Alchemer line.
Though... Arcana just feels lame. Three shot with no outstanding features. Unless you count the feature of not having outstanding features as one.
Alchemers involve your stupid switch shooting. I don't have the dexterity and speed for that sort of crap, but if you do then that's good for you.
Capable of ricocheting standard fire at a high enough star level.
Has some pretty lame knockback ability and it's pretty much a toy gun that shoots ping-pong balls without switch shooting.