You must first ask yourself, what am I doing with this vinyl?  The simple answer really is that any adhesive vinyl is good for just about anywhere.  However there are some different characteristics that make certain types better for certain applications. 

The most popular type of vinyl sold for machines such as the Cricut is Oracal 631.  This is a calendared film with a water based temporary adhesive.  This is a fantastic vinyl for many different reasons.   First of all it is affordable.  There are some vinyls out there that have some superior performance characteristics, but they cost an arm and a leg.  This film is among the least expensive out their and you really get the most bang for your buck out of it. 

This film also has the removable adhesive.  Often people think that this means it can be peeled up and stuck down again and again.  That may be true for a time or two depending on all the circumstances, but most likely it is really only good for one application.  The best part about this adhesive is that it is just aggressive enough for most applications, not to strong not to weak.  Another common misconception is that this vinyl can’t get wet.  That just simply is not true. Water will not hurt this or most any vinyl. 

So this is one of the best general purpose products.  Now with that being said we will move on to the “outdoor” type of vinyl.  Oracal 651 is often considered an outdoor vinyl.  This doesn’t mean that it cannot be used indoors.  Oracal 631 is often considered indoor vinyl but it can be used outdoors as well.  The “outdoor” vinyls typically have a more aggressive solvent based adhesive.  The films themselves are also more resistant to UV rays.   These types of vinyl are often designed for use on vehicles which experience some very harsh outdoor weather conditions.  The only real downside is that the highly aggressive adhesive can be difficult to remove sometimes and can cause damage to more delicate surfaces. 

Oracal 651 is much like Oracal 631 in that it is designed to perform well at a good price.  It may well be the best all around vinyl for all it’s characteristics.  There are other types of outdoor vinyls that have their place such as Oracal 751 and 951.  These are sometimes referred to as permanent vinyl.  Oracal 651 is pretty much just as permanent as these are, but the 751 and 951 have a slightly longer lifespan for outdoor applications. 

Finally there is heat transfer or T-shirt vinyl.  This of course is for adhering to fabrics.  All the other types of vinyl have a pressure sensitive adhesive just like an ordinary sticker.  You know what happens to a sticker on fabric.  It’s good for awhile and then it falls off.  T-shirt vinyl uses heat to activate and attach to fabric.  It will also attach to many other substrates but is specifically designed for fabric.