Best REEL TO REEL blank tape?

Well first I will tell you that recording your vinyl to open reel is going to become an expensive undertaking. Unless you have some very prized collectable albums your money would be better off spent on a higher end Analog to Digital converter like a Apogee rosetta 200.
Transfer your vinyl over to a computer based server connected to your audio system

To answer your original question, pass on the Maxell tape at best you will only be able to purchase NOS tape. Who knows how it was stored. That will always be a mystery. Not to mention the hassle competing in some Flea-bay auction for a few NOS tapes that are bid up well beyond what they are realy worth.

Go to US recording online and purchase fresh RMGI tape for a consumer level deck. If you have a Studer A-810 Otari 5050 or something further up the food chain you can give the ATR tape a try.
ATR is great tape for 15ips recording and do make excellent live recordings.
For what you are going to pay for 10+ year old Maxell tape you will be close to new RMGI and this will help to support both companies to continue to produce new fresh stock

Why not try one of each and compare? Also, your deck might've been tuned to record best on particular brand and model. Have you had it aligned and cleaned recently?
I don't know much about R2R but for my Nak I use Maxell Vertex tape which is by far the very best. I did hear that the Maxell tape you mentioned is excellent.
Great project, by the way. I do the same but with cassettes so far. Might get R2R later though.

Found the Maxell tape to be excellent. The TDK tape very fine as well. Most of my LP to tape transfer done with the Maxell brand. Loads of fun. That being said. Apachef1 comments makes a lot of sense.
For myself having a R2R was the most fun of all my gear. It was a great joy. And this hobby is not always about what makes the most sense. I have not used mine in some time and finally will seek to sale my Teac X-10. So if you are in the market for one or two overpriced questionably stored nib 10 inch reel tapes email me.
By the by the Pioneer is a sweet deck. Nothing beats a R2R for the joy.

Why put vinyl on tape? Just keep the vinyl and maintain a good turntable. I have few R2R decks together with a large collection of commercially pre-recorded tapes. These tapes sound great, many of which were commercially recorded from vinyl and used in broadcast applications. Analogue sound is much better then digital. I have found little sense in taking any of my vinyl and putting it on tape. I do not do vinyl to digital transfers either, too time consuming. Better to just enjoy the music.