Higher NAV better ?

We cannot view a mutual fund unit like a share. There is no 'saturation point' as far as the growth of the Net Asset Value of a fund is concerned. An individual stock may get over valued if its price shoots up, but that is not the case with a unit trust.

Now, let's look at the NAV. 

Basically, it is irrelevant how high or low the NAV of a fund is.Let's say you want to invest RM 5,000. Irrespective of which fund you invest in, this amount stays constant. Now let's say that your choice is restricted between two funds with identical portfolios. Since they both have identical portfolios, their value will increase in the same proportion. You may buy the units of one fund at a higher price than the other. But, the percentage increase would be the same. Hence, your investment of RM 5,000 will increase by the same percentage, irrespective of the fund you invest in. So the number of units you get as well as a high or low NAV are irrelevant. Thus, it is the stocks in a portfolio that determine the returns from a fund, the value of the NAV being immaterial.

You should be making your selection of mutual funds based on past performance, risk and other such factors.

The only instance where a higher NAV will get you fewer units that may affect you is where a dividend has to be received. 

Dividend is given per unit. So the fewer the units you get, the lesser the dividend.