My Radio Shack iron that I use at home takes forever to heat up, and sometimes I think it isn't even done heating up by the time I'm done. The old Hakko 936 I use at work heats up in 45 seconds.
Radio Shack iron tips suck. I get much more mileage out of the tips I use at work.
If yours continues to work for you, then go for it. Mine did, too, until I used the Hakko. It's just that much better.