I just dumped the Moment after they did not have any more replacements to give me (original plus 5 and still didn't work right). I now have the Transform and other than the phone being slow and laggy and the screen lock not working half the time I like the phone. But i just can't figure out what the deal is with Sprint. If you don't shell out the cash to buy the highest high end phone you get left behind with update and maintenance releases for your phone. I hope that they will live up to their word, which hasn't always been so good, and give us the froyo release that Samsung says will "fix all of the problems you are experiencing with the phone". I can't understand the problems that Sprint is having in releasing this build because almost every other carrier has fully released froyo already. I don't know if it is the conversion to Sprint's CDMA network or if it is just all of the Sprint BS they force into the builds that is taking so long, but they need to fix whatever problem they are having or hire some of these other guys to their geek squads who know how to get the job done right.
I am in the same boat as you. I got the Moment within the first week of launch and went through a bunch of these fighting with issues concerning UAD, Airplane mode, and the thing freezing from lack of memory.
The Transform is actually much better than the Moment. I don't have to pull the battery everytime I use wifi, nor do I have to worry about airplane mode. One thing that I have discovered is that it helps to just do a factory reset every now and again when it starts lagging out instead of trying to clean up your system. This phone isn't great, but it does what the Moment was supposed to have done. The only problems I have are the landscape issue(which is easily fixed with launcher pro), and sometimes it will back out of any app you enter until you hit the back key a few times. The only good thing is that it will get me through until I upgrade to something substantially better. If I was out shopping for a new phone, I would just pony up the difference and get an Epic or an EVO.
I think the Optimus is the best phone that Sprint has to offer. It effectively runs just as fast as my friend's Evo and is an excellent design/construction. I am very pleased with my Moment upgrade selection. I'm just relieved that my phone works consistently. In my personal opinion, I'd rather have a phone that works all the time than have a "better" phone that works 90% of the time.