I think a lot of it is personal preference. If you are going to lock your dish down on a single satellite, using only C-band, and use a modern receiver or PC tuner card, to me it makes far more sense to simply upgrade the feedhorn/LNB to a newer integrated model that uses voltage to switch the polarity, similar to the way that small dish LNB's are switched by voltage. The reason is that switching is instantaneous and is unaffected by extreme cold or hot weather, plus it is much less expensive to go that route than to buy a controller. That is what I did; I have several of the old mechanical switched feedhorn/LNB combos in a box somewhere (including a C/Ku combo unit that's probably the same as what you have) and I personally would not even think of using one of them again.
But if I were going to receive both C and Ku using the same dish, or if I were going to try to scan the entire arc using a single dish, I might think differently. Well, probably not in my case, I just find the newer LNB's so much easier to set up, and to me they do a much better job. Also, I like the fact that you can get dual C-band LNB's so you can run multiple tuner inputs accessing the same dish, particularly on satellites that have a lot of good C-band signals. But I can understand that those older units do seem to work better for C/Ku combos, and also have the advantage that the skew can be adjusted in case you are tuning a satellite where the skew is slightly off. There also the upside that you can peak the skew from inside the house rather than while standing on a ladder in front of the dish, but if you are going to lock a dish down on a single satellite, chances are you'll never have to peak the skew again after the initial installation.
I will admit those older feedhorns were much better built mechanically than some of the newer stuff, but still, to me it just seems like the newer polarity-switched integrated feedhorn/LNB's yield a bit higher signal strength. YMMV. Also with regard to the newer ones, there is some real junk being sold on eBay, so be careful where you buy. I'm not saying you need the most expensive model out there, although in some cases there is a reason for a slightly higher price, but there is a lot of bottom end junk that is much more likely to die on you when the temperature gets too cold or too hot, or give you other weird problems.
