The way I see it, if it can't be done with 5 rounds of .357, It probably won't get done with 7 
It really depends on your purpose tho... +2 probably isn't THAT much heavier. However, it will be thicker. For CCW, personally, we went with the 605.
(Just checked taurus'es website... 605 weighs 24oz, 617 weighs 28oz, not a LOT of difference..)
If it was a house gun, or, a range gun, I'd go with the 7, so reloads are slightly less frequent.
You're probably best off to rent each, and play around for a bit
If considering for CCW, try to borrow one from a buddy, or, see if the shop will let you try them both on...
HTH
It really depends on your purpose tho... +2 probably isn't THAT much heavier. However, it will be thicker. For CCW, personally, we went with the 605.
(Just checked taurus'es website... 605 weighs 24oz, 617 weighs 28oz, not a LOT of difference..)
If it was a house gun, or, a range gun, I'd go with the 7, so reloads are slightly less frequent.
You're probably best off to rent each, and play around for a bit
If considering for CCW, try to borrow one from a buddy, or, see if the shop will let you try them both on...
HTH