Really comes down to you and your personal circumstance and goals and how long you intend to hold. Buying the investment means you can claim your costs againsts your earnings, but will have to pay CGT if you sell. You will also have to deal with tenants either directly or through an agent. And of course you will have to pay rent to live where you want to live. Buying your own place means you have the freedom to do what you want to where you live, you don't have to pay rent and don't have the hassle of renting from someone. You don't have to pay CGT on sale but you can't claim costs.
If you are buying now just to get into the market, want to hold the original investment but want to buy your home where you want later - its probably better to buy the investment now. That said you can always make your current home an investment down the track but you will only be able to claim costs from that point and you will begin to lose any tax free status re CGT.
Very hard to know whats best for you - you really just need to crunch the numbers using the scenario you intend/want to follow.
