First of all I like them so much that it is hard for me to be objective. But I’ll try.
 
sr325e are open “on the ear” dynamic headphones. Top of grado “prestige” line that includes 60, 80, 115, 225 and 325 models. “E” in the name means enhanced (if I’m not mistaken). The cable is very thick and the overall design looks a bit weird. They are handcrafted in brooklyn and the build quality is not always perfect.
 
The sound. The soundstage and separation is very good. On binaural recordings it is hard to believe that the musicians are not in your room. Seriously. The bass is nice, but not the best. The impact could be better. However it’s not bass that makes them special. It’s mids and highs. They are crystal clear, very upfront, crunchy and aggressive. That is what makes a “grado sound” that is usually either loved or hated. There are a lot of controversies in opinions. Some say that they are for rock only and not enjoyable with jazz or classics, some say that they are not good for electronic music. Some say that they are astonishingly good for everything you throw at them and I agree with this. There are some imperfections in sound (but these are not summit-fi headphones after all). However listening to rock sends shivers down my spine and I just can’t get used to it. They act as an arrogant and aggressive bandit but in a good way. If that makes any sense. The guitar riffs never sound like that (not even close) in any other headphones I tried. The jazz sounds amazing. The saxophone is just like never before.

sr325e are not neutral allrounders. They are just very special. I would recommend trying them for a number of tracks. Led Zeppelin, Guns and Roses, ACDC or anything similar would be a good showcase of what they can do to you. And then you may or may not like them. Actually the model doesn’t matter that much if you would like to understand what “grado sound” is. The signature will be the same even on sr60 that are sold for a fraction of the 325 price.

20+ years ago I used to have a chinese portable tape player. It had very bad build quality, extremely cheap materials and was slooooowing down the playback as the battery was running lower than 50%. After that I had a couple of Sony walkmans and the discman that were much better. Many years later smartphones (and later iphones) emerged and I thought that dedicated portable music sources are part of history. There was a moment when I thought of getting the Pono player. However I was never able to justify this purchase for myself. Nowadays things are getting different.

What I`m holding now is the chinese dedicated portable hi-res music player (DAP as it`s usually called). From the first touch you realize that it has nothing in common with my first tape player. It’s made from a solid high-grade aluminium piece with a beautiful finish. It feels like tank. Heavy and sturdy. Built on Android and this makes it flexible and full of features rarely available on devices with proprietary OS. The touchscreen is responsive and nice. The contrast and viewing angles are not the best and generally it’s not at the level of newest iphones. But IMO it`s perfect for the purpose. I wouldn't want to pay extra for the DAP top-tier screen. The resources should be mostly spent to fulfill the main purpose of the device - the sound quality.

This is my first DAP so it is hard for me to compare with the direct competition. However comparing to Audioquest Dragonfly (v1.0 that is built on the same DAC chip by the way) and FIIO e17 I’m very happy with the sound. Here I`d like to note that the default amplifier module (Am1) is the weakest part of the device in my opinion. I would recommend to get it with Am3 (Am2 and Am5 should be good as well, but I haven't heard them personally). Lows are tight and punchy, mids and transparent and detailed, Highs are very detailed. If I try to find something to improve I will say that the mids can be more forward and there is a slight spike in highs that can be sibilant sometimes. But that is really minor to me and don’t bother at all. The soundstage and instruments separation is great. With Am3 module the battery life is not among the best (5-6 hours of playback) but for me it’s not an issue. X7 forced me to re-listen all my favourites as it revealed so much details that I couldn`t pick up before. Especially on DSD recordings. The piano pedals pushed down, subtle breathing, fingers touching strings, background noises and echoes. The first DSD album I played was “Jazz in the Pawnshop” by David Chesky records and it overwhelmed me. Of course the headphones used should be on the same level with the device to open the full potential.

To sum this up - the X7 is like having a hi-fi system in a pocket. Nice sound and drivability (with am3) great usability. The bettery life is not the best and the firmware is a pain at the moment. Hopefully FIIO will polish it soon.