中联重科YZK21压路机的优点包括：1. 功能强大：中联重科YZK21压路机具有高效的土壤、砾石、沥青等压实能力，能够满足不同工程的压路需求。2. 易于操作：该压路机采用先进的液压系统和电子控制技术，操作简单方便，可根据需要进行多种操作模式的切换。3. 稳定性高：中联重科YZK21压路机采用重心低、重量均匀分布的设计，能够提供稳定的工作状态，提高施工安全性。4. 燃油经济性好：该压路机采用高效节能的发动机和液压系统，燃油经济性好，能够降低施工成本。5. 维护方便：中联重科YZK21压路机采用了 modulis-soft 结构化电路设计，易于维护和保养，减少了停工时间，提高了工作效率。总结起来，中联重科YZK21压路机具有功能强大、易于操作、稳定性高、燃油经济性好和维护方便等优点，能够满足各种工作环境的压路需求。

The advantages of Zoomlion YZK21 roller include:1. Powerful function: the Zoomlion YZK21 roller has efficient soil, gravel, asphalt and other compaction capacity, which can meet the compaction needs of different projects.2. Easy to operate: this roller adopts advanced hydraulic system and electronic control technology, which makes it easy and convenient to operate, and can be switched to multiple operation modes as needed.3. High stability: Zoomlion YZK21 roller adopts the design of low center of gravity and even weight distribution, which can provide stable working condition and improve the construction safety. 4. Good fuel economy: This roller adopts energy efficient engine and hydraulic system, which has good fuel economy and can reduce the construction cost. 5. Easy maintenance: Zoomlion YZK21 roller adopts modulis-soft structured circuit design, which is easy to maintain and service, reduces downtime and improves work efficiency. To summarize, Zoomlion YZK21 roller has the advantages of powerful function, easy operation, high stability, good fuel economy and convenient maintenance, which can meet the road roller needs in various working environments.