My favorite 2-3 RD's to invest in if stealth isn’t needed is the 9500I or V1 and of course if price is a concern the 8500X50.
This is some of the primary points to consider:
V1 positives:
Very sensitive.
Simple design (old school)
Arrows V1 negatives:
A bit too sensitive (chatty)
Programming is not easy/logical.
Antiquated design. 9500I positives:
Sensative/acurate but not overly sensitive.
GPS TrueLock & Marking.
Easy to use with ton's of cool features. 9500I negatives:
Too quiet/advanced for some diehards.
TrueLock can be tricky in some situations.
Sensitivity isn’t a V1. 8500X50 positives:
Price/feature benefit
Good sensitivity
Easy to use. 8500X50 negatives:
Not as sensitive as V1 or 9500I but close.
Starting to get out dated.
Price is higher than some Bell units with similar sensitivity for less.
I also like the Bel STI a lot, it has similar sensitivity to the V1 & 9500I if you need stealth.
In the end you need to decide what best suite’s your specific needs/budget weather it be Whistler, Belscort or the good old V1.
Most RD's you can get to know and love pretty quickly, the only exceptions are the V1 & 9500I that take a bit longer to get to know/use. I recommend 2 months to really appreciate what those 2 RD's can do.
If you don’t the V1 will seem too chatty/sensitive and the 9500I will seem too quiet/less sensitive.
I have seen too many V1's returned because of chattiness, and it can be programmed to be a bit quieter.
I have also seen too many 9500I's returned because of the misinterpretation of features and warning-alerts.