When it comes to saws, pick a brand that has good dealer support if you aren't going to work on itself. Echo is on that good brand list.
If you are only using it once in a while for small stuff realistically the modern battery saws from the big names are really hard to beat.
Ideally, stay away from homeowner saws. Farm/ranch saws like your 455 have a good reputation, but I have never actually ran a 455.
My 70+ saw collection is all pro saws or old enough that the lower grade saw was the pro saw with a different cylinder.
Things like skimpy non adjustable oilers are not things I like.
If it matters, I have been Husky, Stihl, Jonsered and Echo certified in the past.
If something 50ish CC is what you are after, for new, 550XP MK2 or a MS261 Stihl are the way to go. I know in the states you can still get the 261 with a normal carb. Personally I haven't delved I to autotunes yet, so I have no opinion.
MY ported first gen 261 is a fun saw to run
Stay away from the 271, 291 etc. They tend to be pretty heavy for their performance. Same goes with the older 029 etc.
With Stihl, on the MS saws, if the middle number is even it's a pro saw, 0series saws it's the last number. MS460/046 for example
Older saws, 346XP, it's brethren the 351 and 353(same cases, different cylinder) are very good choices, the old 55 is a decent saw as well. Not a personal favorite as I am a bit of a snob and have a 254xp as well, but parts are getting scarce for those.
On the Stihl side, the 026/MS260 is a personal favorite, and ported they run VERY well.
My truck saw is heavily ported, base and squish band cut. Normally runs a 16" .325 NK setup, but it currently has a 3/8 20" setup on it.
I tend to build lots of older Huskys on the 162/61/66/266/268/272 chassis, very popular locally.
If you are really bored I can point you towards my Tik-Tok and YouTube and listen to me ramble about mostly older stuff... Lol