These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Game Breaker: Many people cite the Triple Blade as the game's Metal Blade equivalent, due to having large damage and spread for low ammo cost.
Hilarious in Hindsight: All that talk in the old days about Mega Man X being the 10th installment of the series is a whole lot funnier now that there actually is a tenth installment...
Scrappy Weapon: Thunder Wool. It is nigh impossible to aim, and blows through all its ammo in 6 shots. To make matters worse, the cloud can be destroyed if an enemy or projectile collides with it. This means you can't reliably use it at close range or in a tight corridor, since that pretty much guarantees that it'll disappear before it can fire off a bolt, thus wasting a ton of your ammo.
To quote one Gamefaqs poster "Anything the Thunder Wool does, another weapon does better and for less ammo cost."
Tough Act to Follow: Coming after the acclaimed Mega Man 9, this game tends to get this status. General consensus is that it's a good game but not quite as good as 9.