I bought a U3000 for the radar parking mode. I managed to get the U3000 with rear cam for £400 with two discounts. I feel even this was rather expensive, but certainly cheaper than the RRP of £529.00. I got it after having my car vandalised twice - in both instances the Viofo A139 I had caught nothing as it had powered down due to not being driven a few days - even though I had set voltage cut off to lowest, and replaced battery with the largest AGM one I could fit.
Fortunately no vandalism attempts since, but I would love to actually catch someone and have viable video evidence that can convict someone in court.
If image quality for budget is top priority, then the Viofo dashcams are the clear hands down winners.
If you need a low power parking mode that lasts for more than a couple of days, get the U3000. I also leave a power bank with a WIFI USB hotspot in the car, and even in radar parking mode it will notify of impacts. Note that unfortunately impacts can include cars merely driving past if parked on a main road. I think in my situation, concerned about potential vandalism, I would get it again - but only if discounted.
I'd love to think a firmware update could add HDR to the U3000, but it's quite possible the hardware is not capable of processing - even though the sensor used is. Also the last firmware update date suggests they're not quite eager to release updates.
