At first,

Remote event receivers are mainly introduced for cloud or office 365 environment (SharePoint Online) where the core logic will run in an hosted environment outside of SharePoint Sites and still try to achieve the regular event handler functionalities.

You can still develop them for as SharePoint Ad-In's even in 2013 server but i will list out couple of major differences here:

1. Remote event recieverers have lot of complexity because you need to setup the app domain, app-catalog, trust and so on as they can be hosted in cloud or another iis server.

2. Core logic will run outside of the SharePoint site calling a custom or out of the box web service, trigger workflows to handle the actual events.

Now coming to your two requirements, ITEM Added and Adding events in the regular SharePoint Farm solution are best suitable for you to add or append the html and also it (Item Adding event) can stop/prevent the event firing during the course based on the conditions of the field values.

if you want a future proof solution, then you should consider using remote event receiver else you can opt for the standard Farm solution based event receivers.

At first,

Remote event receivers are mainly introduced for cloud or office 365 environment (SharePoint Online) where the core logic will run in an hosted environment outside of SharePoint Sites and still try to achieve the regular event handler functionalities.

You can still develop them for as SharePoint Ad-In's even in 2013 server but i will list out couple of major differences here:

1. Remote event recieverers have lot of complexity because you need to setup the app domain, app-catalog, trust and so on as they can be hosted in cloud or another iis server.

2. Core logic will run outside of the SharePoint site calling a custom or out of the box web service, trigger workflows to handle the actual events.

Now coming to your two requirements, ITEM Added and Adding events in the regular SharePoint Farm solution are best suitable for you to add or append the html and also it (Item Adding event) can stop/prevent the event firing during the course based on the conditions of the field values.

if you want a future proof solution, then you should consider using remote event receiver else you can opt for the standard Farm solution based event receivers as you can achieve this functionality with both.

At first,

Remote event receivers are mainly introduced for cloud or office 365 environment (SharePoint Online) where the core logic will run in an hosted environment outside of SharePoint Sites and still try to achieve the regular event handler functionalities.

You can still develop them for as SharePoint Ad-In's even in 2013 server but i will list out couple of major differences here:

1. Remote event recieverers have lot of complexity because you need to setup the app domain, app-catalog, trust and so on as they can be hosted in cloud or another iis server.

2. Core logic will run outside of the SharePoint site calling a custom or out of the box web service, trigger workflows to handle the actual events.

Now coming to your two requirements, ITEM Added and Adding events in the regular SharePoint Farm solution are best suitable for you to add or append the html and also it (Item Adding event) can stop/prevent the event firing during the course based on the conditions of the field values.

At first,

Remote event receivers are mainly introduced for cloud or office 365 environment (SharePoint Online) where the core logic will run in an hosted environment outside of SharePoint Sites and still try to achieve the regular event handler functionalities.

You can still develop them for as SharePoint Ad-In's even in 2013 server but i will list out couple of major differences here:

1. Remote event recieverers have lot of complexity because you need to setup the app domain, app-catalog, trust and so on as they can be hosted in cloud or another iis server.

2. Core logic will run outside of the SharePoint site calling a custom or out of the box web service, trigger workflows to handle the actual events.

Now coming to your two requirements, ITEM Added and Adding events in the regular SharePoint Farm solution are best suitable for you to add or append the html and also it (Item Adding event) can stop/prevent the event firing during the course based on the conditions of the field values.

if you want a future proof solution, then you should consider using remote event receiver else you can opt for the standard Farm solution based event receivers.