I've owned both, and do like both.
But to me, the FF70 is a "masterpiece"...

I’ve never fished the FF605 but have several rods shorter than 7’; in general, I like the longest rod I can get away with and the sub-seven footers only go to the tightest streams where I (almost always) have experience with 7’ rod.

I have an early FF70, and it’s a great match for most of my small streams, where the casting distances match your description. So, I’d favor the FF70 over the FF605, certainly as a single purchase.

But I’d be remiss if I didn’t give what I think is the best advice; get both. If you decide you don’t want to keep one, you’ll almost certainly be able to sell it here for about what you aid for it.

FF70

Here's my ff70 from 1965 in action.
My all time favorite,small stream, summertime
rod.

The 7' rod is probably more useful, but I do love a 6', 2oz Fenwick.

Not always about what's most useful, but some days what rod says fish me as your walking out the door. For me, although there might be thirty or forty rods sitting there, many days I would take the 6' Fenwick.

Hey upstream,
That fish was caught from the stream pictured.
And it's in north Carolina, not far from the ga state line.
You've probably fished it.

Guys, great input and love the pics from Swamp. I put in the order this afternoon for the FF70. Looking forward to using it on fish about the size of Swamps.

Saving my $ and on the look-out for an FF 806.

This forum rocks...........

Ff70 smoother caster more versatile. But there are few rods I’ve had more fun with a fish on than the 605. Get both. For that size range tho I think the 605 would bring you more joy

Swamp, is that a Bronson 360 hanging from your FF? What a classic combo!
Elwha, you made a great choice...

adding to the FF70 chorus

I'm glad the OP got his answer quickly. The FF70 is a magical rod.

There are some very nice Fenwick rods out there, but for classics, the FF70, FF806 and FF85 are hard to beat. I would say the FF80, since I normally I like two digit Fenwicks, but the FF80 is more of a 6/7wt rod. I like the action of the FF75 too, but when I walk out the door to go fishing, my FL96-6 (FF806) goes with me.

The FF60 (and FF605), FF79 and FF84 are all wonderful rods for their purposes, but aren't quite the "every day rod".

I really like the FF705 for small, brushy streams as it is a superb roll caster. The FF70 seems a little faster and more of a dry fly action rod. Maybe better for more open small streams but I'll go to a longer rod for them. Easier to keep line off the water with a 7' rather than 6' rod, and because of the roll casting ability the FF705 will cast well in tight spots.

Kevin