Not to be a party pooper, but I can tell you honestly, a plate chiller is very hard to keep clean. I used one for almost five years (shirron and then a therminator) and they are nearly impossible get completely clean without tons and tons of backflushing (both ways), soaking, etc.
That said, I never had an infection either, so its not like its a high risk, but that drawback is definitely real, so much so that it caused me to give up on them when considered in conjunction with the hassle of using them as well.
#1 Use a screen in your kettle. I have a homemade hop stopper and it works great to keep everything (except the cold break) out of the chiller, even on my recent Pliny clone.
#2 Backflush and purge with PBW immediately after your brew session. If you already have a pump, just save the output of your chiller water (which will be warm) in your mash tun and use that to recirculate. This will clean your hoses, the pump, and the chiller all at once. Easiest part of the cleaning session.
#3 If you want, you can bake it in the oven to kill anything left over in there. You can also run hot wort through it before you start chilling to sanitize your hoses, pump, and chiller without worrying about sanitizer.
I haven't heard of anyone I know who uses a plate chiller having infections, so I don't think it's something to worry about unless you start getting them.