Things aren't looking good for my 2nd edition musketmen.
I'm going to leave aside the theoretical soldiers for now. In 2nd edition the strength and dex scores don't have an impact below 16. I didn't give that score to any of my 3rd edition/D20 modern characters, so I on't dwell on it too much. With a bit of a nod to the concept of masterwork, bows with a cost of 3-5 times the book rate are mentioned to be able to deal extra damage as normal for the character's strength bonus.
The composite longbow, costing 100 gp, is listed with a Rate-of-Fire of 2/1, which means two arrows loosed every round, even for a level one fighter. The 500 gp arquebus, on the other hand, has an RoF of 1/3, one shot every three rounds. This jibes pretty well with the later versions, except that in the second edition of Advanced Dungeons & Dragons, a combat round lasts one minute. I'm told that a "player's option" book brought combat rounds down to 10-15 seconds with a "standard round" still taking one minute. No matter how long a round supposedly is, our bowman lets slip 6 arrows to one shot fired by an arquebusier. [As an aside, my spell-check doesn't like "arquebusier". I think it's correct, but it suggested a corrected spelling of Albuquerque.]
Damage is a complicated subject, with either weapon. The composite long bow, with a sheaf arrow, deals d8 damage with each strike. with range increments of 40, 80, and maximum bowshot of 170 yards. At medium range the attacker has a -2 penalty to their shot, and long range has a -5 penalty. With flight arrows, dealing only d6 damage, the numbers are 60, 120, and 210 yards maximum.
The arquebus has a comparable range, 50 yards medium, 150 yards long, and maximum range of 210. However, range penalties are doubled with that weapon, meaning that from 50 yards they will have a -4 penalty, and a difficult 150 yard shot carries a -10.
It's worth noting that the game of Advanced Dungeons & Dragons, most combat takes place underground, or in buildings, and those range increments are in yards, not feet. So multiply that 50 yards by 3, and divide by five, that means medium range doesn't start until 30 five-foot squares. Combats are generally smaller than that on my gaming table. Perhaps I could remedy that, but it's difficult using a grid map and miniatures 3.5 style to have bigger fights. So for personal level, rather than mass-combat engagements, I don't believe range is a significant factor here. I suspect the more modest ranges of weapons in 3.5 is because of this issue.
Anyways, the arquebus damage is weird. It's a d10 with an footnote: When a arquebus scores a hit, it normally does 1 to 9 points of damage on 1d10. When a 10 is rolled, the die is rolled again and this amount is added to 10. Each time a 10 is rolled, the die is rolled again and added to the previous total. Thus, in a rare instance, a single shot could inflict 37 points, for example, if three consecutive 10s were rolled, followed by a 7. The damage caused by an arquebus is never modified for a high Strength score.
The game also seeks to punish you for choosing this weapon, with a 10% chance of failure on each shot: If the attack roll for the arquebus is a 1 or 2, the weapon backfires, causing 1d6 points
of damage to the firer. It is also fouled and cannot be used again until it has been cleaned,
which takes about 30 minutes.
So, the arquebus.... Drastically slower to fire, possibility of doing a lot of damage with one hit, but just as likely to blow up in your face. The longbow can attack twice per round, with a modest damage output and no chance of blowing up in the user's face. The longbow has a longer accurate range, but most players won't encounter more than medium range in combat. Both have the same ease of use per the rules, which are a simple pass/fail of weapon proficiency.
I don't think I have any more sources available, unless I start looking at actual historical resources, like wikipedia. Let's do that next time, shall we?