A lot of these arguments hold no weight at all for a main firewood saw.
For starters, if you want the grunt of the 5100, in the block, the 346 needs some type of muffler mod. Mod the original cat as Brad says and kiss your warranty goodbye. Buy a non cat muffler and spend even more money on top of the original $80-$100 up charge of the 346 but you may be able to just put the cat muffler back on and still have a warranty.....You know, what they don't know won't hurt 'em kind of deal....lol
As for as inboard clutch versus outboard clutch....Inboard all the way.....What happens if homeowner pinches his bar trying to fell a tree with an outboard clutch? Get out Wildthing try to cut saw and tree free
tree comes down smashes $500 Husky.
With Dolmar inboard clutch.....Remove clutch cover, then remove saw from bar, get $400 - 5100 out of harms way
.....Go kill yourself with Wildthing to save $40.00 bar and chain.....Son inherits perfectly working 5100.
As far as filters go....346 has better filtration but 5100 isn't that bad.....I have cut all day with a 5100 and never needed to clean or replace the filter till the work was done......If that is a necessity for you....Try sharpening your chain!