Rear roller I’d always recommend a hayter although not the best with wet grass…I have the 48inch pro version..gets used on the ‘posh’ lawns
Commercial properties I normally use a Husqvarna Klippo mulch mower..love it ..lightweight ..good speed….Honda engine ..manoeuvrability excellent…not so...
For small lawns (definition?) I tend to use a small battery powered mower ..convenient..lightweight ..not so good on wet grass and when long (be prepared to double cut) …maybe tie it in with other machinery you might need such as strimmer..hedge cutter …so that the battery (can be expensive) and...
Pffft ….I have three lawnmowers sunshine ..two of which I would classify as professional..the other would suit Icy Gull.
As regards to the OP more info is needed…what size is normal (we still talking lawns?)…budget etc etc etc etc etc