Spitfire Symphonic Motions and Evo Grid 3 both provide rhythmic solutions for composing, but there are some significant differences listed below:

Symphonic Motions is a dedicated plugin which loads directly in your DAW, whereas Evo Grid 3 is a Kontakt library, meaning that it is loaded inside of the Kontakt Plugin, and requires you to have bought a full copy of Kontakt from Native Instruments.

Symphonic Motions is has a large ensemble which is "Symphonic" in scale, whereas Evo Grid 3 has a much smaller chamber sized ensemble.

Symphonic Motions has some of the most commonly found rhythmic values such as 6th, 8th, 12th, and 16th notes played both discretely and smoothly across a number of techniques whereas Evo Grid 3 contains rhythmic evolutions, that evolve slowly over time, often quite dramatically.

Symphonic Motions is was recorded in AIR Lyndhurst Hall, whereas Evo Grid 3 was recorded in the smaller, and drier, AIR Edel.