'deem preferable' is correct and usable in written English.
You can use it when you want to express that something is considered to be more desirable than something else. For example: "We deemed the smaller size preferable to the larger one."
The quiet of languid country-town streets was deemed preferable to the absolute silence of whole abandoned blocks.
Instead of complexity, the rule seems to be all fruit, all the time, with power deemed preferable to elegance.
It's very good indeed on the contentious area of collusion in abusive relationships, where the "attention" of maltreatment is deemed preferable to the catastrophe of indifference.
It boasts high levels of polyunsaturated fats, in particular linoleic acid, which for some is not that good of a thing – opting for high oleic sunflower oil is deemed preferable.
At the most recent gathering, at least as much time was spent discussing the virtues of various thickening agents — finely-ground tapioca and corn starch were deemed preferable to flour — as to the book itself.
Laos, which is much smaller and weaker, has in recent years given the impression of being overrun by Chinese, something that many cadres deemed preferable to being pushed around by Vietnam.
Particularly in Pashtu-speaking areas in the south, swift (and often brutal) Taliban-administered "traditional" justice is sometimes deemed preferable to the sluggish and corrupt courts provided by the state.
A slight increase in transmission power at a node to cover a neighbour node is deemed preferable to having another (closer) node retransmit.
For this reason, it has often been deemed preferable to use only scalar data at high latitudes rather than use vector components that are more sensitive to high latitude current systems.
Contraindications to intravenous CEUS are severe cardiopulmonary dysfunction and known hypersensitivity, whilst it has been deemed preferable to avoid intravenous CEUS in pregnancy because of an absence of clinical data.
The third pie chart, the one almost no one deemed preferable, represents the actual distribution of wealth in the United States.
