The Marco Polo seems to be popular with many (I spoke to a fellow passenger who had travelled on 7 voyages) but I suspect that those who like this 54-years-old ship are the same as people who choose to drive a 54-year old car rather than a new one. Not because it is better but because it is different.
The eccentricities and signs of age are apparent as soon as we had embarked at Cardiff and were shown to our cabin (number 130 - chosen by the operator as we had elected to a guaranteed outside cabin rather than choosing one). The first thing one notices is that there are only two electrical sockets - a 220 volt continental point and a 110 volt US point (plus an unnamed push button whose use we didn't bother to determine). In 1965 travellers probably only needed one point - but with the plethora of electrical appliances that are the stock in trade of the modern traveller, one power point is not really adequate.
The cabin lights were also rather primitive, with an array of ceiling lights none of which could be switched separately - it was all on or all off using the one switch by the cabin door - and two separate reading lights.
The cabin was adequate although, in common with the majority of cabins on this vessel, had twin beds that couldn't be pushed together. So not to be recommended for honeymooners.
Impressive but not easy for those less fleet of foot.