It depends on your own motivation.
The difference is in the steering mechanism; 'roller boots' (now called 'quad skates' because the wheels are attached at the corners) are less stable in a straight line. The 'tilt&turn' chassis is like a small skateboard under each foot, so you can make very agile turns. They are excellent if you like weaving & dancing, and want to skate in a small area, like a parking lot or leisure park.
'Roller blades' (also called 'in-line' or 'linear' skates, because the wheels are set out in a single row underneath) will also weave and turn, but not so easily as quad skates do. These skates are much better for long-distance, and (with extra-large wheels fitted) high speed. The best of these have more wheels (typically, five on each skate) and a longer chassis, sticking out quite a way behind and in front of your foot. The technique is smoother and more 'gliding', and most turns are made with a 'crossover' or 'stepover' action. Because longer routes are more suitable for this kind of skates, they are often sold as 'fitness skates'.
Both types are used for roller hockey, because individual players have their own preferences for skating style. Ramp skating was invented for quad skates, but is now performed exclusively on the linear type. Mainly, this is because using a single row of wheels (or sometimes just the front and rear wheel on each skate) allows the 'shelf' under each side of the skate to be used as a platform for 'grind' stunts.
Ramp & Grind skating is very good for fitness (but may carry more risk of injury), so you should consider the possibility of learning this style along with the others when making your choice of skates.