I have used sink tips and really don't like them but I know a lot of folks that do so I think it is a matter of personal preference. What you are comfortable casting and using. I prefer a weight forward (WF) slow sink (type 1 or type 2) full sinking line (in my case, a WF-5-S), especially for Specks. It gives them more time to see the fly on the drop and when I retrieve the fly, the line is straight to the fly with no severe downward arc so I can detect bites better. However, I get different results in fly action depending on whether I use unweighted or weighted flies. The fly should drop at less or the same rate as the line for unweighted flies but should drop faster than the line if weighted. Both situations may be an advantage or can be a disadvantage at different times. I also like to use a fluorocarbon tippet on my leader for the sinking line especially with unweighted flies because it pulls the fly down better. I only use the sinking line when the Specks are deeper than the leader on my floating line can reach them. Just my personal preference though.Originally Posted by crappiecrazy
Here are two articles that discuss both kinds of lines. Links below.
Joe Cornwall likes a slow sink full (uniform) sinking line but also uses a fast sinker at times.
A Calico Time of Year
Tom Keith likes the fast sink tip or fast sinking line anyway.
Wet Flies for Big 'Gills and Crappies