One thing to bear in mind with resin is SAFETY!
Always wear a mask when sanding, the dust is very harmful to you. One way to get around this is to sand under running water, though you then have to wait for the parts to dry.
Never allow the dust to come into contact with too much heat, don't put it into an ashtray for instance, a hot cigarette will produce phosgene gas, if you're lucky you'll wake up in the emergency room, if not....
Resin can be cut easily with a razor saw, but again, dust!
Resin can be shaved & cut with a scalpel quite easily, unless it slips....
Superglue & two part epoxy glues work well with resin.
Resin often contains holes from 'bubbles' in the mould, fill with superglue & rub smooth, but again, dust!
Yes, resin is hard, thin bits may shatter or break as you cut them, repair with superglue.
To sum up, it can be good to use resin parts, you'll get more detail than with injection moulded parts, but always bear those safety tips in mind & plan what you're going to do before you do it, One idea is to get some 'tack rags' from a paintshop & wipe down your work area regularly.
Hope this helps
Pete