I really-really wanted a .35Whelen for many years. I even ran up on a hunter using one and he was really fond of it.
When push-came-to-shove, and I decided to rebarrel my MkX in .30/06, I ended up buying a .338/06 barrel. (was on sale at a rediculously low price).
I don't regret doing the .338 but I really still wish I had a .35Whelen.
I have a Marlin M336 in .35Rem and it's a real thumper on deer. Almost too brutal with the 200gr Remington Corlokt RN run up to 2300fps (easy with H4895).
I have a Parker-Hale in .30/06 that I keep thinking that I want too rechamber.
The only regret that I have with the .338 is that there are no "inexpensive" bullets available for it. Midway and others sell the 200gr Remington Pt.SP Corlokts and that would be my primary bullet for the .35 as it is for most of my other calibers. The last time I wanted to rechamber my '06, (not the .338), I ended up buying a used Savage M110 in .300RUM for way too cheap.), then a Weatherby (Howa) Vangard in .257WbyMag. I also bought 16lbs of WC-860 for $50, so I don't really "need" a .35Whelen.
If I had it to do over again though, I'd definitely go with the .35Whelen.
If you shoot a .35Whelen, you definitely need to invest in $100 worth of loading equipment. You'll then have ammo for life for the cost of bullets, powder, and primers. Just this afternoon at the local public range, I picked up over 100 .30/06, .270, and .25/06 brass. Any of these with a single push through the loading dies creats either a .35Whelen, or .338/06.
You'll find that either of these two, at under 300yds are quite a bit more gun than the .30 caliber. I easily get 2,800fps with my .338 and 200gr bullets, and 3,000fps with the discontinued Nosler 180gr B.T. (however they do make the "accubond" at 2x the price ...............)
The Remington 200gr CorLokt will produce 1.5moa accuracy and will do 90% of what you want to do with the Whelen. Even the 200gr RN will hold together at the speed of the Whelen, just don't expect as much penetration as with the 200 Pt.SP.
The Hornady 200 and 225gr are excellent bullets also. Don't forget the 180gr Speer FN. It shoots suprisingly flat and is tough enough for the Whelen.
I say go for it, especially if you can find a Rem. 7600, or the new 750.
I once had a 760 in .35Remington. It was exceptionally accurate (sub-moa with 200gr Sierra RN and either H322 or Imr3031).
I however, don't care for the foward placement of the "slide" and the fact that it will rattle.
Make my .35Whelen a bolt action.......... about 8lbs with a 2.5-8x Leupold VX-3.