Buying new sails is always a neat thing to do - there aren't many experiences that beat putting up a new sail for the first time.
These days with CAD, you will rarely get a bad new sail, but a Vyv implies, its how the sail is going to be in 5 years time that really matters.
A large part of the reason that Hood sails are so good is the fact that they manufacture their own cloth, and, I think everyone, even other sailmakers would agree that Hood sails outlast the rest by a substantial margin - probably last at least twice as long and still keep their shape.
The important considerations when ordering a new mizzen are------
Don't buy the cheapest cloth, buy the most expensive if you can.
Don't buy a sail made from highly coated/tempered fabric, they are fine for racing but after a year or so, the coating cracks off and the sail starts distorting. Make sure the weight of the cloth is adequate, I would suggest a minimum of 8oz (whatever that is in metric) - unless you buy from Hood.
Make sure the sail is cut very flat, a bigger belly looks more powerful, but you don't need it and in a breeze it will distort and require continual fiddling with halyads and outhauls (the latter not being easy on a mizzen). Also bigger bellied sails don't last as long, over time the flow runs aft as they stretch.
Personally I wouldn't go for a loose foot, in a breeze they rattle against the boom, they add considerably to the loads on the outhaul fittings (mine self destructed last autumn because of this).
Don't be tempted to have a large roach, it looks good, but the sail won't last as long. After all it is a cruising boat!
As it is a mizzen, it is likely that the sail will be used in very strong winds - small jib, no mail and full/reefed mizzen, if you want the sail to last, consider asking the sailmaker to triple stitch it - wont cost much more but it will last a lot longer. Also for this reason (used in a lot of wind) get the sailmaker to use stainless steel shackles on the sliders, the nylon ones often let go in a big breeze, esp when hoisting and lowering or when putting a reef in.
If you don't want to go to the expense of a Hood sail (and I believe they aren't that much more) I have seen some nice looking ARUN sails around. After all its not a racing pedigree that you need but a long lasting nicely cut sail.
Trust this helps.