Working at small firm vs large firm

Hi, I've been recruting for an m&a role and got an offer to join a tiny regional firm as an analyst (4 people, <25m deals). I've been told to avoid small firms in the past because:

"Fees will be low and the processes will likely be pretty loosely run and without too much complex analysis or training in terms of modeling, deck building etc."

How true is this statement? 

Regarding processes, if seller is motivated to sell asap and you are able to find big company looking for targets for a roll-up, how loose can it get? Everyone is motivated to close it asap, due to small company size I'd image there would be less legal hurdles and better communication, plus, like I said if you're selling to large strategic investor (maybe even a public company) with a good corp. dev. department they wouldn't stall without good reason. So where does looseness come from?

Regarding complexity, as far as I know when working on a sell-side all you need to do is cook up an operating model for CIM based on management assumptions and MD comments, what's the difference if business is 5m or 500m EBITDA, most of it will rely on dubious future revenue assumptions based on "market research", OPEX, NWC, CAPEX trends will be elucidated by the management. So where does the complexity come from? Is it because in 500m EBITDA business it is easier to bury faults which might spring up during DD? 

To me this job opportunity sounds great: working at a small firm with lots of companies in many industries and getting significant responsibility due to lean team size. But maybe am wrong and shouldn.t take it?

Thoughts?

Thanks