Customization of the buttons just plain looks better

It’s really only a few CSS changes and typically you (as I did) can find different posts on the web for to help you start your process:

Placement –

Marketo CSS inside the form > settings > theme > gear icon > edit custom css

Mautic CSS inside custom CSS of your CMS system – in this case wordpress.

Screen Shot 2016-06-29 at 11.59.48 AM.mktoForm input[type=text], .mktoForm input[type=url], .mktoForm input[type=email], .mktoForm input[type=tel], .mktoForm input[type=number], .mktoForm input[type=date], .mktoForm select.mktoField, .mktoForm textarea.mktoField{
box-shadow: 0px 3px 1px 0px rgba(20, 57, 94, 0.1) !important;
border-radius: 0 !important;
border: 1px solid #999999 !important;
padding: 15px 15px !important;
color: #999 !important;
margin-bottom: 7px;
}

.mktoForm fieldset legend {
font-weight: bold; font-size: 18px
}

.mktoButton {
background-color: #4CAF50 !important;
border-radius: 0 !important;
text-transform: uppercase !important;
background-image: none !important;
border: 1px #ffffff !important;
font-size: 20px !important;
width: 200px !important;
border-radius: 0 !important;
text-transform: uppercase !important;
color: #fff;
font-weight: bold;
padding: 10px 20px;
box-shadow: 0px 3px 2px 0px rgba(20, 57, 94, 0.1) !important;
text-shadow: none !important;}
}

.mktoButton:hover {
background-color: #ffffff !important;
color: #4CAF50 !important;
border: 1px solid #4CAF50 !important;
}

div.mktoHtmlText.mktoHasWidth > p > span > a{
font-size: 12px;
color: #666;
}

Screen Shot 2016-06-29 at 12.01.59 PM.mauticform-button {
color: #357fbe !important;
margin: 8px auto 0;
cursor: pointer;
font-size: 16px;
font-weight: 500;
-moz-border-radius: 1px;
-webkit-border-radius: 1px;
border-radius: 1px;
padding: 3px 20px;
line-height: 1.7em;
background: transparent;
border: 1px solid;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
-moz-transition: all 0.2s;
-webkit-transition: all 0.2s;
transition: all 0.2s;
}

.mauticform-button:hover {
background-color: #357fbe;
border-color:#357fbe;
color: #ffffff !important;
padding: 3px 20px !important;
}

.mauticform-input, .mauticform-textarea, .mauticform-selectbox {
background-color: #ffffff !important;
margin: 8px auto 0;
border: 1px solid;
border-color:#357fbe;
width: 80% !important;
-moz-border-radius: 1px !important;
-webkit-border-radius: 1px !important;
border-radius: 1px !important;
font-size: 14px;
color: #333 !important;
padding: 3px 3px!important;
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
box-sizing: border-box;
}