Some letters are used for the same .....
It is about :
- PW (43*-49* depending on brand/model)
- AW or GW (ca. 49*-52*....)
- SW (ca. 54*-56*....)
- LW (ca. 58*-60*....)
- XW (ca. 62*-64*....)
There are other things to consider aswell, bounce for instance .....
For a decent description of bounce use the search function of this forum, plenty of good info !
The amount of bounce in a set's PW is mostly around 7*-8* and most GW/AW are in the line of bounce that matches a set's PW ..... so around 8*
In a SW the bounce will prevent the club to dig into the sand too much and will help you to get the ball up by sliding under the ball, bounce in SW comes in several options, as there are several styles of bunker play and also there is a lot of difference in sand conditions in bunkers, as the might be white soft sand but it can also be hard sand ........ I would say that if you want something allround 12* bounce will be nice for a SW and if the sand is very hard it is best to use the 8* bounce AW/GW to get out of the bunker.
LW and XW are hard to control for any beginner ....... why ....... hmm hard to tell, it should not be, but in general it is, you have to hit them with some force to pop the ball up in the air and a 60* wedge might give a beginner a 40 yds shot. Chances of blading or thinning a 60* wedge are huge for a beginner, so if you have a shot of 45 yds to the hole ...... you'd think of hitting a full LW, which is a nice looking shot if you succeed, but if you thin or blade it, it will end up 40 yds beyond the hole........ better is to take out your 7 or 8 iron and hit a chip or longer chip, if you hit that a bit thin or heavy it will still end up on the putting surface........
Do you need a AW/GW ...... as a beginner ........ not really, but it is a way better investment than a LW.
In some strong lofted sets the PW is 43*-45* and then the gap to a 56* SW is really big, in which case you about have to buy the AW/GW ......
So for a beginner I would say you need the set's PW + SW (with 10*-12* bounce) and extra might be the in between AW/GW