Unlike Bach who favored the Vivaldi style of three movement concertos, Handel used the older forms of concertos used by Corelli, which had four movements. Handel was primarily a composer of opera (42 of them), and after the decline of his popularity he concentrated on writing oratorios (29 of them). But he did compose in most forms of the Baroque era.
The beginning movement of Handel's Concerto Grosso in A Major takes the form of a French overture, characterized by dotted rhythms and interplay between the string orchestra and the two solo violins. After a few slow chords from the strings, the French overture continues with a short four-part fugue. Another short transition section links the fugue with the next movement which is in ritornello form. A theme is played by the string orchestra that alternates with virtuosic material played by the soloists. Each time the theme returns, it undergoes a change but retains its basic characteristics. The last movement continues in ritornello form with soloists answering the orchestra in quick paced music. There is a short section in F-sharp minor, but the music returns to the tonic with a final call and answer section between the soloists and the orchestra as the music makes its way to the end.
While the majority of Handel's works suffered from neglect for many years, a few pieces remained in the repertoire, namely his oratorio Messiah, and some opera arias. But even these few exceptions to general neglect were usually recast in more modern guise for contemporary performance. But with the practices of Handel's time when he thought nothing of using bits of other composer's music in his compositions or arranging his own music for different ensembles, it may not have upset Handel too much.
Mozart was not known to have been very kind to other musicians, especially composers. Handel was a composer that Mozart understood (even though he fell into the group of musicians that rearranged Handel's music, notably Messiah) and who allegedly said:
Handel understands effect better than any of us -- when he chooses, he strikes like a thunderbolt.While Mozart may not have said those words, with the modern revival of performances of Handel's music as he originally wrote it, the sentiment is true enough.