I have the SPF 70, and no other Sea Pathfinders. At the time I wanted something solar powered and with compass - those two criteria restricted my choice enormously.

As you say, it is bulky, but it does have a large, clear (digital) display so at least the space is good for something. As its solar powered I can't comment on battery life, but I have noticed that in winter its state of charge has dropped to "medium".

Apart from the features I've already commented on, I like that the timer will count down from up to 24 hours. I have known other watches which only counted down for an hour, or didn't have the feature at all. It has multiple alarms, which I'd find more useful if I didn't use my phone for that kind of thing nowadays. I use the stop watch for timing lunch breaks.