It is difficult to draw those comparisons since they are two very different investments. Basically the fees are much lower with funds since you not have to pay IMT but you have more risk - “safe” when it comes to a fund is very much a relative, there are no guarantees, and returns in Portugal are low. Why this is, has been discussed extensively in the main fund thread -
https://community.nomadgate.com/t/portugal-gv-fund-comparison.
Though now that many funds have started having setup fees of 3-5% the “savings” of funds is debatable and now it comes down to a fixed 3% (which is really less than that since you do not get 3% for the full 5 years) versus whatever returns you think the fund will actually pay (which may or may not be the same as what is promised).
The summary is:
You buy mercan because you want real estate and want something very safe and very easy and do not want to have to think and are willing to pay for that. You buy into funds because you can accept some risk and want lower fees. I almost did mercan, I almost did property. I did funds because of IMT and because at the time I did not have to pay setup fees and I thought the returns would be higher. Now, I might choose mercan just to get the lower 280k investment number. Neither is better. They are all different. You will not find a concrete answer. Do not seek comfort in “what other people are doing”. Only you know which works better for you.