i was in the same boat, ended up with the 715t carry handle junk. first time out it had major fail to feed issues. by the third mag, it was basically a single shot. i got excited if i got 3 rounds off in a row. sent it back, on mossberg's dime after fighting with them that they were paying to fix and ship it. while talking with them before sending it back, i mentioned how i could not get it sighted because it shot low, about 3" at 30 yrds low. the front sight is non adjustable and the rear needs raised to raise the point of impact. i had more adjustment on the sight, but the carry handle came into view and blocked the front sight from view all together. i asked if i could buy the flat top shell(it is basically the 702 model with just 2 pieces of plastic bolted on to it). they said no, not possible.
after waiting 3 weeks for a shipping label it went back. i also included a note stating all of my issues and the wish to buy the flat top shell, as well as the original mag and the extra i had purchased. they "fed exed" it to me exactly a week after the received it. i was told the replaced the trigger housing assembly. i opened up the box and there were 3 mags and a flat top shell on my gun.
i was happier than a pig in poo until i fired it. each mag would have a fail to eject at least 6 times out every 25 rounds. the original mag and the freebie were def. worse averaging 10-15 fte per loading.
i again contacted mossberg by email this time(working ot could not call them) and got a reply 5 days later. i replied back, with more questions. i have yet to receive a reply, and that was from october.
i sent the gun back again, they received it the day after thanksgiving and i got it back 2 weeks later. it seems to work well now, although i have only been able to get another 150 rounds through it since, but there has been no fail to feeds and only 3 fail to ejects.
i had plans to sell it and get the smith instead just because of the lifetime warranty as opposed to the remainder of the one year warranty on the mossy, but the wife has nixed that. after all of that, i am happy with the gun, it is fun to shoot, and pretty accurate. i could do it all over again, i would get the s&w.
my friend also has one...after a trip back to the factory to fix a cycling issue(fail to feed i believe), he has quite a few thousand rounds through it since last april...no issues now according to him.