Pro You can choose your own play style
In Warframe, there are tons of weapons, both ranged and melee, that will let you fight however you like. Maybe you want to be a long-range sniper, or a massive melee beast with a huge hammer, or maybe you want to stick closer to the ninja tradition and use a sword and a bow. Whatever you prefer to play, Warframe has an option.
Pro A huge array of weaponry
Warframe boasts over 300 weapons, split into 3 classes: Primary, Secondary, and Melee. Primary weapons are the big guns such as assault rifles, shotguns, bows, and grenade launchers. Secondary weapons are the sidearms, usually handguns, machine pistols, and thrown weapons. The melee weapons consist of swords (even katanas), hammers, fist weapons, scythes, and others.
Most of the weapons have their own unique strengths and weaknesses. For example, the Simulor is a weapon which creates small balls similar to black holes, which pull in and kill enemies. Unfortunately, the range is very short, so you'll have to predict enemy movements and place the shots carefully. Another example is the Zarr, a massive canon, which has two firing modes, allowing you to use it as a canon or a shotgun. The downside is that you'll get damaged by your own explosions, so you have to always keep distance.
The weapons can also be upgraded, adding various elemental damage types such as radiation or corrosion. You can also improve other stats such as rate of fire, crit or reload speed.