Both have their advantages and disadvantages, and for me, they fit different types of investors.
If you're the type that is very disciplined when it comes to saving and investing, and you have the time to study what investment options will give you the best returns, then monitor the market to make sure that you're buying units of MF/UITF or stocks at the right time and take advantage of any market opportunities, then term is the best type of insurance for you.
VUL on the other hand, I would recommend for 4 types of people. First, those who are new to investing, and are not used to setting aside money for the purpose of investment, so they can get used to the habit. Since mas mahal ang VUL sa term usually, it lets people get used to committing themselves to setting aside a bigger portion of their money.
Second, if you are the type who wants riders or have a family history of critical illness (like cancer) because ang term usually accidental death lang rider ang pwede i-attach na rider, ang VUL maraming possible riders kang pwede i-attach sa policy.
Let's be honest, kapag nagkasakit ka ng critical sa first few years ng term insurance, ubos yung investment mo kahit mas malaki pa ang kinita nya kesa sa VUL, dahil ang term, makukuha lang ng family mo ang benefit pag-dead ka. Eh paano kung kailangan magpa-chemo or magpa-heart bypass? Syempre dun sa investment ka kukuha, eh di parang nawala lang sya.
Third, if you just want to have insurance and invest but are too lazy to learn about what your other options are, or are just plain not interested in the time and effort to find out about other investment vehicles (and yes aminin natim, may mga ganitong tao).
And lastly, for older people who are already in the stage of estate/inheritance planning. Una dahil mas mahal na ang premium ng term kapag older ka, so wala na syang difference sa term premium-wise, plus usually may medical requirement. And second, it's easier to get a single-pay VUL for each person na pamamanahan mo kesa mag-divide ka ng pera, stocks at properties, at magbayad ng transfer taxes para sa bawat isa sa kanila.
Mathematically-speaking naman, all projections will tell you that BTID performs better. Assuming of course, alam mo yung ginagawa mo sa pagi-invest. If not, pwedeng isang taon pa lang ang pera na ininvest mo, ubos na due to losses.