As an early respondent to this thread and having recommended sealed units I can understand the reason why someone would favour replaceable bulbs. However, it all depends on each person's preferences and how they have arrived at that choice. My own unscientific preferences for outside lights is to go for sealed units particularly LED fittings. This preference is based on previous experience, we had a number of bulkhead lights at the last house but once they started to need bulbs replacing nearly all started to let moisture in. Again unscientifically I reasoned that this was occurring because once the seals were disturbed after long compression they never seemed to compress quite the same and in the case of my bulkheads further compressing the shade to body seal was causing the seals under the screwheads to disintegrate thus allowing moisture in. I have had the same occur at our present house to halogen floods, so far the replacement sealed LED ones have not leaked but only time will tell. Maybe it is down to gut instinct I feel something factory sealed will remain sealed longer than something you are trying to seal whilst dangling off a ladder.

Other reasons for choosing a particular type of fitting is aesthetics. Removable bulb units tend to be bulkier whereas the units I fitted recently are quite discrete for the amount of light they give off.

At the end of the day you choose what suits you with the features that are important to you. I think the replaceability of bulbs might be a consideration and it is valid to recommend that just as I recommended sealed units and why. It is up the OP to weigh up the recommendations put to them and I for one would not get upset if my recommendations are ignored.

Richard