I'm a big fan of Escort radar detectors. If you want the best buy the Escort Passport 9500ix. It has excellent long range detection for the highway and in the city it does not give you many false alerts. A matter of fact it learns your driving routes via Gps and locks out false signals after they are detected a couple of times. It alerts you about red light cameras again with GPS and the software can be updated via the internet when new red light cameras are added.
You want to be sure when your radar detectors goes off that you take it very seriously. If it is always giving you false alarms you begin to ignore it and then when it's a real threat you are caught off guard. I would suggest buying the very best if not you will be paying the difference with the speeding tickets you accumulate. Yes a great radar detector can be pricey but it will more than pay for it self over time.
I have learned over the past 25 years that you are best off not speeding. That is the easiest way to avoid a ticket. But for those moments that your not paying attention to your speed or the road opens up and you want to have a little fun having a great radar detector is essential for protecting yourself. Mine has saved me so many times I have lost count. Oh by the way I have not had a speeding ticket in over 10 years.
My last tip, if you are going to speed with a radar detector always have a rabbit. What's a rabbit? It's someone who is already driving 5, 10, 15, 20 mph over the speed limit. This rabbit is the person you follow. Obviously if a police officer is shooting radar they will most likely get the ticket first but I believe more importantly you will be alerted via your radar detector that a police officer is ahead, giving you plenty of time to react and slow down.
Best of luck.