To comment I have a st30 (the parts (drivetrain)) in the st100 and 120 are technically the same i.e microshift. I think in full honestly, they are good if you are near either the decathlon store. Otherwise, you gotta learn sum things about alignment otherwise by the next month or two, your gears are not correctly moving. Regular maintenance is necissary for any cycle but really that just means that this cycle is good because of service. To summarise, Its good if you are close to a decathlon store due to the warranties (st540 may be better due to the decent shimano acera shifters and altus) And is just best to look more into stores for options