The net asset value (NAV) of an ETF is based on the current prices of the stocks/assets in the fund and an actual accounting of the total cash in the fund at the time of calculation. Market price can be different from real time NAV due to late market activity and both tend to converge periodically. A market price close to real time NAV is much better for investment!
ETFs charge their shareholders an expense ratio to cover the fund’s operating expenses, which is expressed as a percentage of the fund’s average net assets. This directly reduces the fund’s returns to its shareholders, and, therefore, the value of the investment. Lower is always better!
Less expense ratio implies better returns over the long term
Tracking error is the difference between the performance of the ETF and that of the underlying benchmark it's tracking. It's an important metric for investors who want to replicate an index's performance by investing in the ETF. The lower the tracking error, the better is the ETF's performance aligned with the investor's expectations
Return vs FD Rates
Fixed Deposit rate is a virtually risk-free rate where the investor assumes almost no risk on their investment. If the ETFs price return is lower than this rate, investors are better off investing the amount in a FD
High demand for an ETF increases its price. If the price is pushed up to a level which is not justified, then it's considered to be in the overbought zone, which is not a good time to buy the ETF