Generally it is harder to play the guitar with your fingers than it is with a pick. The reason for this is the complex movement involving guitar finger picking when compared to the simple motions when using a pick. Granted, there are variations that can become harder with the pick then they are for fingerpicking (like arpeggios), but that is not the general idea.

There are several styles of guitar finger picking, ranging from classical to flamenco. Intermediate styles like jazz involve using both a pick and your fingers alternatively in order to produce different effects and sounds.

Classical finger picking doesn’t rely so much on anything other than arpeggios and a primitive form of picados. Though some classical songs involve different techniques, they are generally focused on the sound quality rather than being challenging. Jazz and acoustic styles also use arpeggios as the main technique and again are not very challenging since not much speed is required. The focus of all these styles is comfort and relaxation.

In contrast, flamenco is a very complex genre, and it involves several right hand techniques that are unique to this style. The best flamenco guitarist in that he has mastered every technique in existence is Paco De Lucia. His trademark technique is the picado. The picado is the technique in which you use your index and middle fingers alternatively for rapid picking of the strings. Done right it sounds like a flurry of notes with the feeling of a galloping horse. Coupled with the fast nature of flamenco and an excellent control over the left hand patterns the result is remarkable in both speed and power.

Any exercise is good to practice your picado, that is everything helps, both exercises for thumb or arpeggios are very good. These will help you improve your guitar finger picking a lot.