Downgrade to Nautilus 3.4 from Ubuntu 13.10 / Nautilus 3.8

I'm going to risk answering this question since I now feel I have collected enough information on this issue. Basically downgrading to Nautilus 3.4 seems not to be an option at this time; it was coded for an earlier version of GTK, thus it wont compile on Ubuntu 13.10. The only practical way is installing a different file browser.

As it happens, Nemo is actually a fork of Nautilus 3.4 that has kept all the features of the latter (adding a few more). I've been using it since yesterday and the interface is almost the same, a seamless transition for the user. Thus installing Nemo is not very far from downgrading to Nautilus 3.4. I haven't done it yet, but it is possible to set Nemo as the default file browser.

All features I used in Nautilus 3.4 seem to function properly in Nemo (e.g. Connect to Server). The only exception at this stage is the integration with RabbitVCS, there's a package available but non functional at the moment. Since RabbitVCS doesn't work on Nautilus 3.8 either, it is not a regression.

Update II: There's no need to install Cinnamon, just install the Nemo package:

sudo apt-get install nemo

Update I: Nemo's appearance can be tweaked into something closer to the default Unity style. Open its css file:

sudo gedit /usr/share/themes/Ambiance/gtk-3.0/apps/nemo.css

And then replace all contents with the following:

.nemo-pathbar-button,
NemoPathbarButton {
background-image: -gtk-gradient(linear, left top, left bottom,
color-stop (0, shade(@dark_bg_color, 1.1)),
color-stop (.3, shade(@dark_bg_color, 1.1)),
color-stop (.7, shade(@dark_bg_color, 0.90)),
color-stop (1, shade(@dark_bg_color, 0.80)));
border-color: shade(@dark_bg_color, 0.7);
-NemoPathbarButton-border-radius: 3px;
}

NemoPathbarButton:active {
background-image: -gtk-gradient(linear, left top, left bottom,
color-stop (0, shade(@dark_bg_color, .8)),
color-stop (.3, shade(@dark_bg_color, .9)),
color-stop (1, shade(@dark_bg_color, 1.0)));
border-color: shade(@dark_bg_color, 0.7);
}

NemoPathbarButton:hover {
background-image: -gtk-gradient(linear, left top, left bottom,
color-stop (0, shade(alpha(@dark_bg_color, 1.4), 1.25)),
color-stop (.3, shade(alpha(@dark_bg_color, 1.4), 1.25)),
color-stop (.7, shade(alpha(@dark_bg_color, 1.4), 0.95)),
color-stop (1, shade(alpha(@dark_bg_color, 1.4), 0.85)));
border-color: shade(@dark_bg_color, 0.7);
}

NemoWindow * {
    -GtkPaned-handle-size: 1;
}

NemoDesktopWindow GtkWidget {
    background-color: @transparent;
}

.nemo-canvas-item {
    border-radius: 4px;
}

/* desktop mode */
.nemo-desktop.nemo-canvas-item {
    color: @bg_color;
    text-shadow: 1px 1px alpha (#000000, 0.8);
}

.nemo-desktop.nemo-canvas-item:active {
    background-image: none;
    background-color: alpha (@bg_color, 0.84);

    color: @fg_color;
}

.nemo-desktop.nemo-canvas-item:selected {
    background-image: none;
    background-color: alpha (@selected_bg_color, 0.84);

    color: @selected_fg_color;
}

.nemo-desktop.nemo-canvas-item:active,
.nemo-desktop.nemo-canvas-item:prelight,
.nemo-desktop.nemo-canvas-item:selected {
    text-shadow: none;
}

/* browser window */
NemoTrashBar.info,
NemoXContentBar.info,
NemoSearchBar.info,
NemoQueryEditor.info {
    background-image: -gtk-gradient (linear, left top, left bottom,
                                     from (shade (@cluebar_color, 1.02)),
                                     to (shade (@cluebar_color, 0.98)));
    background-color: @cluebar_color;
    border-bottom-color: shade (@cluebar_color, 0.92);
    border-radius: 0;
    border-style: solid;
    border-width: 0px 0px 1px 0px;

    box-shadow: inset -1px 0px shade (@cluebar_color, 1.02),
                inset 1px 0px shade (@cluebar_color, 1.02),
                inset 0 1px shade (@cluebar_color, 1.04),
                inset 0 -1px shade (@cluebar_color, 1.01);
}

NemoTrashBar.info:backdrop,
NemoXContentBar.info:backdrop,
NemoSearchBar.info:backdrop,
NemoQueryEditor.info:backdrop {
    background-image: -gtk-gradient (linear, left top, left bottom,
                                     from (shade (@cluebar_color, 1.01)),
                                     to (shade (@cluebar_color, 0.99)));
    background-color: @cluebar_color;
    border-bottom-color: shade (@cluebar_color, 0.92);

    box-shadow: inset -1px 0px shade (@cluebar_color, 1.01),
                inset 1px 0px shade (@cluebar_color, 1.01),
                inset 0 1px shade (@cluebar_color, 1.02),
                inset 0 -1px shade (@cluebar_color, 1.0);
}

NemoSearchBar .entry {
}

.nemo-cluebar-label {
    font: bold;
    text-shadow: 0 1px shade (@cluebar_color, 1.06);
}

.nemo-cluebar-label:backdrop {
    color: mix (@fg_color, @cluebar_color, 0.2);
    text-shadow: 0 1px shade (@cluebar_color, 1.02);
}

#nemo-search-button *:active,
#nemo-search-button *:active:prelight {
    color: @dark_fg_color;
}

NemoFloatingBar {
    background-color: @info_bg_color;
    border-radius: 3px 3px 0 0;
    border-style: solid;
    border-width: 1px;
    border-color: darker (@info_bg_color);
}

NemoFloatingBar .button {
    -GtkButton-image-spacing: 0;
    -GtkButton-inner-border: 0;
}

/* sidebar */
NemoWindow .sidebar,
NemoWindow .sidebar .view {
    background-color: shade (@bg_color, 0.95);

    /*background-color: @bg_color;*/

    color: @fg_color;
    text-shadow: 0 1px shade (shade (@bg_color, 0.95), 1.04); 
}

NemoWindow .sidebar .frame {
    border-width: 1px 0 0 0;
    border-style: solid;
    border-color: shade (@bg_color, 0.86);
    border-radius: 0;
}

NemoWindow .sidebar:backdrop,
NemoWindow .sidebar .view:backdrop {
    color: mix (@fg_color, shade (@bg_color, 0.95), 0.2);
    text-shadow: 0 1px shade (shade (@bg_color, 0.95), 1.02); 
}

NemoWindow .sidebar row:selected {
    color: @selected_fg_color;
    text-shadow: 0 1px shade (@selected_bg_color, 0.8); 
}

NemoWindow .sidebar row:selected:backdrop {
    background-image: -gtk-gradient (linear, left top, left bottom,
                                     from (shade (shade (@bg_color, 0.95), 0.94)),
                                     to (shade (shade (@bg_color, 0.95), 0.86)));
    border-top-color: shade (shade (@bg_color, 0.95), 0.88);

    color: @fg_color;
    text-shadow: 0 1px shade (shade (@bg_color, 0.95), 0.96); 
}

NemoWindow .pane-separator {
    background-color: shade (shade (@bg_color, 0.95), 0.94);
    border-color: @dark_bg_color;
    border-style: solid;
    border-width: 0;
    box-shadow: none;
}

NemoWindow .pane-separator:backdrop {
    background-color: shade (shade (@bg_color, 0.95), 0.96);
}