Wow! I'm surprised to find that I am in a tiny minority as one who likes 50/50 serrations!
It's not a clear-cut thing, though.
I love my 50/50 Spyderco Delicas, and I also like my straight one.
I have to admit that I don't do a whole lot of cutting with my EDC Delica. Other posters' experience with 50/50's alleged inadequacies may very well be completely valid -- I just don't use knives enough to have come across such shortcomings. Most of my cutting jobs are just very light-duty. I doubt my EDC knife would be something as, well, flimsy as a Delica if I were really having to beat on a knife. But should a defensive situation arise, or for my average daily chores, I think the Delica with 50/50 does just fine.
I believe I would miss the serrations if I went with an all-straight blade, and I would miss the straight edge and fine cutting ability if I went with full serrations. And I LOATHE the idea of sharpening serrations. I get a nasty edge on my knives with a Profile and I also have a Sharpmaker if I needed to do serration work, but I hate doing it. So on my 50/50 knives, the serrations always go neglected (but they're not real dulled anyway) and the straight sections are always well-maintained.