Big stage race coming up. Being "over 35" I can race either as cat 4 or 35+. I've been hem hawing for a week now. The masters, who I have raced against before, have smaller fields but the race is harder. Plus, it's way more safe than cat 4. The only thing the cat 4 race has to offer is a place to hide from the wind and a slower pace, but there will be loads of squirrelly riders. All races are the same distance no matter what catagory I race.
In the middle of horse country, in The Garden State
I see similar things in comparing CAT4 and 30 or 35+ for the women's divisions. The masters are often an all-CAT race. We'll have some 1's and 2's in there who use it as warm up for their P/1/2 race. Makes it harder for the others to place - so I usually sign up for CAT4.