What makes a saw a "pro saw"?

[ManjiSann]

These had the tar beat out of them .For example one had lost the e-clip on the clutch and was ran with no clutch bearing which had broken the clutch and burned up all the  plastic .Another had all the flocking missing from the air filter with only the wire mesh left which chewed up the cylinder and others just badly abused .The others which are in pieces I'd have to look at the cylinders to try and figure it out .
It wasn't all the saw design because they were just misused .However pro saws such as 034 supers and one 038 Magnum with over 20 years of use held up during that period .Fact the 038 grenaded a piston which I replaced and it continued for about 5-6 years as a daily runner which was given to me and now abides in my shed .Also an 028 also survived and It's right next to it as did a 281 Husky and they are all mine now .
Having said that with the subject of "pro saws " in mind  with just standard maintainence they would have been okay I think . Nothing wrong with them for general usage .

Al, I neglected to mention it's a Husqvarna 390xp. The saws you're talking about appear to be Stihls, guessing on the numbering sequences and associations?  I'm not a brand snob, in my limited experience and from all the reading I've done it sounds like they are both excellent brands. In fact I had also been looking at Stihls as well. I appreciate you popping in to share your thoughts and experiences, I've read a lot of other posts you've contributed to and thus believe you to be very knowledgeable... do you own chickens as well?  :D :D @doc henderson 
From what I've read, whether pro, mid grade or consumer, if routine maintenance is done on it and when there's an issue it's addressed it seems like most saws will run for a long time. Thanks for the details and don't worry about looking at the cylinders on the others, unless you feel like it. From what you said I don't think I'd have the same issues as I'm fairly meticulous about maintenance (the stuff I know about at least  ;) )
The kill switch on one of my poulans stopped working, not really a big deal as you can use the choke to kill it but in my mind it's a bit of a safety hazard so I've already ordered the replacement parts to fix it. It was a rather opportune issue as the Husky I just bought said in the description that the kill switch is non functional but you can kill it with the choke (matches my knowledge/experience so lets me know they seller isn't totally clueless.) Because I'm in the process of fixing the same issue on the Poulan, when I read that in the description it didn't worry me much at all as I was already familiar with it. I pulled the Husky's diagram and it appears to be a pretty similar set up so no big worry for me. 
Would you consider the Stihl 028 a pro level saw? From what I've read it sounds more like the Rancher (in my mind mid grade?) type saws. 
I guess in the end what I'm trying to get at is how to know what level of quality a saw is as I'm likely to buy most of mine used and sometimes people want pro level prices for what is more of a consumer grade saw. Nothing leaves a bad taste in my mouth like thinking I got a great deal only to find out it's not what I thought it was.
Thanks,
Brandon 

[Al_Smith]

The 028 Stihl unless I'm mistaken was the smallest of a series of 3 models of 038,the 042 and 048 Stihl .Gear drive oil pump,very robust  but more  than likely although of a pro design most likely not used in pro type work much because of it's size .I've got one,works,sits on a shelf ,better saws to use .