Having had such a great experience with #6 a couple of weeks ago, I was eager to hear these. As with the Pathetique, I had not, as far as I can recall, heard them since I was in my early 20s. So I did, and it was a mistake.
It was too soon. It was almost impossible that these two works would come up to the level that had just been set by their younger sibling. There is nothing at all wrong with them. They are both good, maybe great, works, and maybe at the right time I would have found, or in the future will find, them as moving as I did the 6th. But as it was they just struck me as being similar but not as good.
It was like falling desperately in love with someone you met only briefly in another town or another country, with which you have also fallen in love, then going home and expecting the next attractive girl you meet to bowl you over in the same way. It's not likely to happen that way.
For what it's worth, though, here are a few impressions:
I must have listened to the Fourth a good many times in my youth, because it was instantly and deeply familiar. So familiar, in fact, that I wonder if the opening fanfare has been used in some movie or TV show. And I liked it a lot, particularly that mostly-pizzicato third movement. But under the circumstances it seemed like a lesser foreshadowing of the 6th. As someone noted in a comment on the post about the 6th, the 4th, in contrast, ends on a note of triumph rather than despair. At the moment that comes across to me as...well, it wouldn't be at all fair to call it a defect, but less powerful, anyway. It does not speak to my condition. Or not as powerfully.
The Fifth, on the other hand, I didn't recognize at all. I listened to it once, fairly attentively, and thought "This is objectively good. I recognize that these are beautiful melodies, potent crescendos. Why am I not responding?" A few days later I gave it another try: put the LP on, listened to the first side (first two movements), and decided I had to let it go. This girl is lovely and sweet and intelligent, but she can't replace my lost love. It's not her, it's me. I must not lead her on. So I put the record back in its sleeve. Someday, at least several months from now, I'll take it out again,
One odd thing: at points during both symphonies I found myself thinking "this sounds like ballet music." I guess what I meant was that it sounds like Tchaikovsky. But I don't remember having that thought during the Sixth.
The performances, by the way, are by Ormandy and the Philadelphia Orchestra. I can't find a date on the box (it's a set of Tchaikovsky's last three symphonies) but the packaging says mid-'60s to me.