I have and have owned Mdl 700's, Vanguard, MKV, Cooper Mdl22, InterarmsMKX, Marlin, Wincesters, Rugers and Browning.
The Howa-Vanguard is actually a version on the Sako L-61. There's a story.
The Mdl 700's are drilled bar stock, fused bolt, washered recoil lug design about as different from the Howa 1500 as you can get and still share the push feed design.
The Howa design is solid and heavy. The receiver is machined from a solid steel billet, not machined from a piece of pipe. The bolt is also machined from a solid steel billet, handle and all, recoil lug is machined integrally with the receiver.
I can't really bash the new designs, all the modern pushfeeds Mdl 700, Tikka, Browning, Savage work really well. The makers pretty much had to change to stay in business.
The pushfeeds were originally designed as a simpler more economical rifle eliminating as many machining steps as possible, from Mauser designs. Excellent rifles were made by Sako, MS, Walther, Schultz&Larsen, ect. Eventually there are the modern versions. The Rem 700 is the first that I'm aware of.
This design became the Chevy small block of riflery. You can make it do almost anything. It can be an economy hunter, a classic sporter, a varmint rifle, a sniper rifle. You can take the design and sharpen it into match winning machine.
The idea that the 700 design is intrinsically more accurate than the 1500 is preposterous IMO. More people build them, simpler and cheaper.
My only gripe about the Pipefeeds is that the only difference I can see between a Tikka and a Marlin, or Ruger American is finish. That a Tikka should cost $200 more than a Howa is absurd!