As a financial assistant, I can provide you with some general pros and cons of buying property in Union Hill-Novelty Hill, Washington based on the information available to me. However, your decision to buy a property in a particular city should be based on various factors specific to your personal circumstances and financial goals.

Pros:
- Prime location: Union Hill-Novelty Hill is located in the affluent Eastside region of King County, close to major cities like Redmond and Bellevue, and offers easy access to Seattle.
- High-quality schools: The area has some of the best-rated schools in Washington, making it an attractive location for families with children.
- Natural beauty: The area is known for its picturesque scenery, with plenty of parks, green spaces, and outdoor recreational opportunities.
- Growing economy: The region is home to several major employers, including Microsoft, Amazon, and Boeing, which bodes well for the local economy and job market.
- Strong real estate market: The real estate market in Union Hill-Novelty Hill has been consistently strong, and home values have steadily increased over the years.

Cons:
- High cost of living: Union Hill-Novelty Hill has a high cost of living, which may be a barrier to entry for some buyers.
- Limited inventory: The area is highly sought-after, which can make it challenging to find affordable properties for sale.
- Traffic congestion: The region is notorious for heavy traffic and long commute times, which may be a drawback for some buyers.
- Regional risks: Being located in the Pacific Northwest, Union Hill-Novelty Hill is at risk of natural disasters such as earthquakes and wildfires.

Again, these are just some general pros and cons of buying property in Union Hill-Novelty Hill, Washington. It's important to do your own detailed research and consult with professionals before making any decisions regarding real estate investments.