Adeptus Mechanicus Skitarii - Used

The Adeptus Mechanicus are part of the Imperium but pre-date the Imperium itself, as they were formally known as the Mechanicum of Mars before they joined the Imperium. They are in charge of making and maintaining all the forge worlds and all the technical operations of the Imperium.

The Adeptus Mechanicus playstyle is flexible and mobile as well as having strong gunline options that can work against horde units and elite units alike. They are very good on the counter charge.

First thing you will need is the Codex for your army which is a book supplement that gives you all the info you need to play and build the army as well as extra lore. The codex you will need is called Codex: Adeptus Mechanicus. The Start Collecting/Combat Patrol boxes are a great choice to start your army because they save you a better amount of money than if you bought the contents separately. Cool units you can buy for the Adeptus Mechanicus are: Cerberys Raiders, Skitarii Rangers, and the Scorpius Disintegrator, to name a few!

Belisarius Cawl is a 10,000 year old archmagos dominus of the Imperium who had a great hand in supporting many crusades over the span of the Imperium. He also helped the Ynnari in the resurrection of Guilliman the Lord-Commander of the Imperium.

The Adeptus Mechanicus are a good army like most armies in Warhammer 40k. If you are seeking a competitive army, then the answer depends on the meta at the time, as every army has their ups and downs in the competitive community. Casual players should not worry about good/bad as it's all about fun.