Nice choice and good feedback!... My only comment would be that a 9' window would be rather cumbersome regardless of who makes it. The proper handling of the units would be incumbent upon the party transporting and/or installing them.

+1

Solid review.

9' windows require lifting straps and some very specific care and handling instructions.

Indeed straps are necessary as you mention. Delivery folks can have tools to deal with them. We would need tools to move them around from where they were delivered. So, I thought it would have been ideal if the straps were attached to the wood like I have had on sliding patio doors I bought from Lowes few years ago.

Couple of more observations:

Flanges (nailing fins) are the length of wood on horizontal and vertical sides - when opened and nailed they leave four square holes in all four corners. Marvin provides a patch for that by including foam gaskets with the windows.

Another interesting thing I realized - and this may apply to many different windows - Nailing fins are made of plastic and they slide into a groove on the window frame. After they are nailed, how much holding power does this mechanism have. There will be additional support from trim inside. Some support when siding is installed. It seems to me that this is an easy way into the house - almost easier than breaking the glass. I have tried neither method, so I am just speculating. Marvin does provide metal straps for windows with mullioned transoms.

Comments?

Those items are all pretty standard across the board, regardless of brand. When installed properly, those windows will not be going anywhere and are no secure risk. The corners of the nailing fin are not a concern either when proper flashing detail is used.
The only units that I have ever gotten with handles are bay windows and patio doors, although Okna does put cardboard wrapped handles on some of their larger windows which is nice. That is really the exception more than the rule though. The vast majority of windows are handled by professionals from the moment that they leave the factory until the time they are installed, so I'm guessing that it is looked at an unnecessary expense.

The fins are not for actually holding the window in place permanently contrary to what a lot of people think. They are to help seal the unit and if nailed thru are generally just nailed to hold the window temporarily while the unit is properly shimmed and nailed thru the jambs.

That would make sense.

There is no mention of doing that though in the Marvin installation instructions.

Also, when jambs are screwed in (I am visualizing interior doors now - having replaced 16 of those myself), shims are inserted from both sides to offer a flat support to the jamb so that it doesn't bow or bend when screws are put in.

Trying similar thing is not possible after having nailed in the nail fins. Maybe, there is a different technique one can use, assuming you are right about putting screws through the jambs.