I expect lots of people are using mesh bodies by now, but I thought I'd just mention a few things about changing over from a classic avatar to a mesh one (head excluded at the moment, I still have my classic avatar head!). I'd only become aware of the Second Life 'revolution' of people changing to mesh bodies when I heard friends Hibiscus Hastings and Ed Follet talking about mesh avatars recently; So I decided to go off and look around the shops for a mesh body.
For those who have no idea what it's all about, the new mesh bodies are much more human looking with details that the classic avatars just don't have (naughty bits on the female bodies and lovely life-like smooth curves!) There are quite a few designer mesh bodies around now, although the men aren't quite so lucky yet, with not such a wide choice of designers, but there are a few men's mesh bodies out there (I don't think they include 'naughty bits' though).
If you already have a nice skin that you don't want to change because you haven't got a new mesh head to match your mesh body, you may be lucky enough to get something called an 'applier' from your skin shop. Luckily my RezzaNova skin shop had an applier that I could purchase that I could use with the Maitreya mesh body 'Lara' which I had bought.
The appliers are hud systems which let you choose layers of clothing (or tattoos) to add to the mesh body, or in RezzaNova's case it's used to tint the mesh body skin colour similar to your RezzaNova skin. When buying clothes for your new mesh body you have to hunt around for clothing that has the appropriate applier. I look for Maitreya appliers when I shop and I recently bought an Omega applier system which also makes the clothes fit (but more about that another time, I'm just learning about Omega!). Without the appliers the system type clothing does not show on the mesh body. I'm still learning, so maybe there is a way you can use an applier, like the Omega system, with clothing already in your inventory, I will have to find out!
Maitreya's mesh body includes the hands and feet as well, some bodies sell these separately. I'd been used to the Slink feet system before I bought the mesh body, (feet attachments where the alpha masks your classic ugly avatar feet and ankles and gives you lovely ankles and gorgeous painted toenails.), so I knew that I would have to buy shoes compatible with the Maitreya feet, and luckily, I can still use the Slink feet with the Maitreya body as well.
One good thing, if you go shopping, you can get away with some mesh outfits without them being labelled as compatible with your mesh body, but be careful, you would have to try on the demo first. The Alpha system on my Maitreya body means I can make any part invisible so it doesn't show through the clothing. But, and there is a big' but', you might come unstuck if you buy a dress and the alpha just doesn't quite match up with the hem of the skirt or the neckline, so you might end up with an invisible space where you don't want it. So best to try stuff on first or stick to buying clothes with the appliers already included.
To add a piece of non-mesh clothing to your mesh body, you simply select the garment (which already had an applier when you bought it) from your inventory and you will be presented with a hud which you click and then choose which part of the mesh body you want the clothing to be put on, i.e. underwear, top clothing, pants, etc. Ordinary prim clothing that attaches isn't a problem, you just add it to your avatar in the same way you always did, so you only have to worry about mesh clothes and system style clothes (the painted on type) for fitting purposes.
I had been a bit upset that my lovely Bax long boots did not fit my new Maitreya body, the Alpha's just didn't cover the right bits, but then, a few days ago I got a message from Bax asking me over to replace the items I already had. Yes the wonderful Bax designer had remade her great shoes and boots to be compatible with the main brand mesh bodies. I was really pleased!
I'm still learning, very probably many people are way ahead of what I've learned so far, so feel free to comment, but I really like the mesh body and it's been an excuse to get some new clothes (did I need an excuse? lol). I've yet to purchase a mesh head though, I'm not keen on the fact that I can't alter the features the way I would like to as they aren't 'modify', at least the ones I saw weren't. You can have fun with some mesh heads though, you can alter the make up, skin tones and other bits, so I would imagine the mesh heads are very popular as well.
Another nice thing about the Maitreya body is that you can change your fingernail and toenail varnish colour, plus you can have short or long finger nails and there are three foot settings for flat shoes, high heels and very high heels.
The way to look at the mesh body is it's just like another layer of clothing, your classic avatar is hiding underneath, masked by the mesh body's Alpha. I'm enjoying finding out about it all and the Mesh body groups are chatting all day long in IM group chat, giving each other tips and helping each other, so it's quite a community!
Avatars in Second Life are getting more realistic all the time. I watched a newbie the other day, he still had his original avatar on and I was quite amazed at how his throat looked so natural, no hard lines and his head turned moving the skin very realistically without the cartoon look about it. That is the only fault I have with my mesh body and classic avatar head, no matter how you try to match the body colour there is still the line around the neck, but it's a small price to pay for such a nice mesh body! I'm really pleased with it!