First off, congratulations on getting your new bolt! I know there are many people out there that have reported having problems ie. txt msg bug, vm icon bug, and the list goes on; my wife and I both have bolts (got them day 1) and neither have given us problems (hers=stock, mine=rooted a month ago). I haven't heard about unpredictable ringtones though, what do you mean? The ringer only decides to go off upon receiving a call or txt msg when it wants to?
As far as comparing the Thunderbolt to the Stratosphere....
For the Thunderbolt, more internal storage (8gb vs 4gb), more RAM (768mb vs 512mb) better gps quality, better rear camera (8mp vs 5mp).
For the Stratosphere, bigger battery (1,800 mAh vs 1,400 mAh), better screen quality, better bluetooth quality, ohh and it has a slide out keyboard (if that's your thing)
Overall I'd say go with the Thunderbolt, but that might be a biased opinion.
*EDIT* here's a link to a comparo
http://geekaphone.com/compare/Samsung-Stratosphere-vs-HTC-ThunderBolt#processing-power