I've been having "problems" with my hiptop. I did buy it second hand (so no warrenty, no insurance) but nothing seems visably wrong with it. The applications work fine. Everything works the way it's supposed to.
It worked beautifully the first month. Then it started to get ugly. I dealt with it losing reception occasionally, then it started to do it often. I called Suncom and they did some "over the air" message and asked me to restart my phone. They told me it was a temporary fix and to call tech support to get a better fix. So I called and get no help from tech support and they wrote on my account to go to a store. I don't want to go to the store because I work screwy hours so I ignore this.
So it works wonderfully, then after a co... (continues)
One option you may wish to exercise before purchasing a new handset is to send your Hiphop/Sidekick directly to Danger the manufacturer and have one of their certified service and repair technicians look at it for you. It may be something as simple as recalibrating the transceiver circuit board which I've seen from time to time happen with GSM/GPRS devices. Give Suncom a call to get the phone number for Danger so you can it shipped off to them.
I say either get the SonyEricsson W810 from SunCom or buy an unlocked Nokia N80 off eBay or somewhere. Typically SonyEricsson phones work GREAT with SunCom... often better than Nokia (especially in Raleigh, Durham, Chapel Hill, Greensboro, and Charlotte). The HipTop3 is good, but not that much better than the HipTop2... Horrible reception problems with the HipTop2 are not normal, and you may be able to get it repaired by Danger (actually it would be Sharp or Audiovox/UTStarcom that would repair it) for minimal cost.
I ended up buying the Sony w810 from Suncom and getting insurance (from my last experience with the phone). I had straight equipment failure. The day I went to get it replaced the email function had stopped working completely on the phone.
What I love about this phone is it picks up reception real quick. If it loses it it picks up ASAP. It does more than I expected.