Вопрос: Чей код чище и удобнее расширятся битрикс или модх?

Лучший ответ:
что угодно лучше битрикса. И да простят меня бывалые битриксойды, но лично я с таким месивом работать не намерен.
Просто кусок кода, который битрикс малый бизнес генерирует после установки в index.phpspoiler<?
require($_SERVER["DOCUMENT_ROOT"]."/bitrix/header.php");
$APPLICATION->SetTitle("Интернет-магазин \"Одежда\"");
?>
<h2>Лучшие коллекции</h2>
<?$APPLICATION->IncludeComponent("bitrix:catalog.top", "", array(
		"IBLOCK_TYPE_ID" => "catalog",
		"IBLOCK_ID" => "2",
		"ELEMENT_SORT_FIELD" => "name",
		"ELEMENT_SORT_ORDER" => "asc",
		"ELEMENT_SORT_FIELD2" => "name",
		"ELEMENT_SORT_ORDER2" => "asc",
		"HIDE_NOT_AVAILABLE" => "N",
		"ELEMENT_COUNT" => "8",
		"LINE_ELEMENT_COUNT" => "4",
		"PROPERTY_CODE" => array(0=>"MINIMUM_PRICE",1=>"MAXIMUM_PRICE",2=>"",),
		"OFFERS_FIELD_CODE" => array(0=>"NAME",1=>"",),
		"OFFERS_PROPERTY_CODE" => array(0=>"ARTNUMBER",1=>"COLOR_REF",2=>"SIZES_SHOES",3=>"SIZES_CLOTHES",4=>"MORE_PHOTO",5=>"",),
		"OFFERS_SORT_FIELD" => "sort",
		"OFFERS_SORT_ORDER" => "asc",
		"OFFERS_SORT_FIELD2" => "id",
		"OFFERS_SORT_ORDER2" => "desc",
		"OFFERS_LIMIT" => "0",
		"VIEW_MODE" => "SLIDER",
		"TEMPLATE_THEME" => "site",
		"PRODUCT_DISPLAY_MODE" => "Y",
		"ADD_PICT_PROP" => "MORE_PHOTO",
		"LABEL_PROP" => "NEWPRODUCT",
		"OFFER_ADD_PICT_PROP" => "MORE_PHOTO",
		"OFFER_TREE_PROPS" => array(0=>"COLOR_REF",1=>"SIZES_SHOES",2=>"SIZES_CLOTHES",),
		"SHOW_DISCOUNT_PERCENT" => "Y",
		"SHOW_OLD_PRICE" => "Y",
		"ROTATE_TIMER" => "30",
		"MESS_BTN_BUY" => "Купить",
		"MESS_BTN_ADD_TO_BASKET" => "В корзину",
		"MESS_BTN_DETAIL" => "Подробнее",
		"MESS_NOT_AVAILABLE" => "Нет в наличии",
		"SECTION_URL" => "",
		"DETAIL_URL" => "",
		"BASKET_URL" => "/personal/cart/",
		"ACTION_VARIABLE" => "action",
		"PRODUCT_ID_VARIABLE" => "id_slider",
		"PRODUCT_QUANTITY_VARIABLE" => "quantity",
		"PRODUCT_PROPS_VARIABLE" => "prop",
		"SECTION_ID_VARIABLE" => "SECTION_ID",
		"CACHE_TYPE" => "A",
		"CACHE_TIME" => "180",
		"CACHE_GROUPS" => "Y",
		"DISPLAY_COMPARE" => "N",
		"PRICE_CODE" => array(0=>"BASE",),
		"USE_PRICE_COUNT" => "N",
		"SHOW_PRICE_COUNT" => "1",
		"PRICE_VAT_INCLUDE" => "Y",
		"PRODUCT_PROPERTIES" => array(),
		"USE_PRODUCT_QUANTITY" => "Y",
		"CONVERT_CURRENCY" => "N",
		"OFFERS_CART_PROPERTIES" => array(0=>"ARTNUMBER",1=>"COLOR_REF",2=>"SIZES_SHOES",3=>"SIZES_CLOTHES",)
	),
	false
);?>
<h2>Тренды сезона</h2>
<?$APPLICATION->IncludeComponent(
	"bitrix:catalog.top",
	"",
	Array(
		"IBLOCK_TYPE" => "catalog",
		"IBLOCK_ID" => "2",
		"VIEW_MODE" => "SECTION",
		"TEMPLATE_THEME" => "site",
		"PRODUCT_DISPLAY_MODE" => "Y",
		"ADD_PICT_PROP" => "MORE_PHOTO",
		"LABEL_PROP" => "NEWPRODUCT",
		"OFFER_ADD_PICT_PROP" => "MORE_PHOTO",
		"OFFER_TREE_PROPS" => array("COLOR_REF", "SIZES_SHOES", "SIZES_CLOTHES"),
		"SHOW_DISCOUNT_PERCENT" => "Y",
		"SHOW_OLD_PRICE" => "Y",
		"MESS_BTN_BUY" => "Купить",
		"MESS_BTN_ADD_TO_BASKET" => "В корзину",
		"MESS_BTN_DETAIL" => "Подробнее",
		"MESS_NOT_AVAILABLE" => "Нет в наличии",
		"ELEMENT_SORT_FIELD" => "sort",
		"ELEMENT_SORT_ORDER" => "asc",
		"ELEMENT_SORT_FIELD2" => "name",
		"ELEMENT_SORT_ORDER2" => "asc",
		"SECTION_URL" => "",
		"DETAIL_URL" => "",
		"BASKET_URL" => "/personal/cart/",
		"ACTION_VARIABLE" => "action",
		"PRODUCT_ID_VARIABLE" => "id_section",
		"PRODUCT_QUANTITY_VARIABLE" => "quantity",
		"PRODUCT_PROPS_VARIABLE" => "prop",
		"SECTION_ID_VARIABLE" => "SECTION_ID",
		"DISPLAY_COMPARE" => "N",
		"ELEMENT_COUNT" => "12",
		"LINE_ELEMENT_COUNT" => "4",
		"PROPERTY_CODE" => array("MINIMUM_PRICE", "MAXIMUM_PRICE"),
		"OFFERS_FIELD_CODE" => array("NAME"),
		"OFFERS_PROPERTY_CODE" => array("ARTNUMBER", "COLOR_REF", "SIZES_SHOES", "SIZES_CLOTHES", "MORE_PHOTO"),
		"OFFERS_SORT_FIELD" => "sort",
		"OFFERS_SORT_ORDER" => "asc",
		"OFFERS_SORT_FIELD2" => "id",
		"OFFERS_SORT_ORDER2" => "desc",
		"OFFERS_LIMIT" => "0",
		"PRICE_CODE" => array("BASE"),
		"USE_PRICE_COUNT" => "N",
		"SHOW_PRICE_COUNT" => "1",
		"PRICE_VAT_INCLUDE" => "Y",
		"PRODUCT_PROPERTIES" => array(),
		"USE_PRODUCT_QUANTITY" => "Y",
		"CACHE_TYPE" => "A",
		"CACHE_TIME" => "180",
		"CACHE_GROUPS" => "Y",
		"HIDE_NOT_AVAILABLE" => "N",
		"CONVERT_CURRENCY" => "N",
		"OFFERS_CART_PROPERTIES" => array("ARTNUMBER", "COLOR_REF", "SIZES_SHOES", "SIZES_CLOTHES")
	)
);?>
<?$APPLICATION->IncludeComponent("bitrix:sale.bestsellers", ".default", array(
		"HIDE_NOT_AVAILABLE" => "N",
		"SHOW_DISCOUNT_PERCENT" => "Y",
		"PRODUCT_SUBSCRIPTION" => "Y",
		"SHOW_NAME" => "Y",
		"SHOW_IMAGE" => "Y",
		"MESS_BTN_BUY" => "Купить",
		"MESS_BTN_DETAIL" => "Подробнее",
		"MESS_NOT_AVAILABLE" => "Нет в наличии",
		"MESS_BTN_SUBSCRIBE" => "Подписаться",
		"PAGE_ELEMENT_COUNT" => "4",
		"LINE_ELEMENT_COUNT" => "4",
		"TEMPLATE_THEME" => "site",
		"DETAIL_URL" => "",
		"AJAX_MODE" => "N",
		"AJAX_OPTION_JUMP" => "N",
		"AJAX_OPTION_STYLE" => "Y",
		"AJAX_OPTION_HISTORY" => "N",
		"CACHE_TYPE" => "A",
		"CACHE_TIME" => "86400",
		"BY" => "AMOUNT",
		"PERIOD" => "30",
		"FILTER" => array(
			0 => "CANCELED",
			1 => "ALLOW_DELIVERY",
			2 => "PAYED",
			3 => "DEDUCTED",
			4 => "N",
			5 => "P",
			6 => "F",
		),
		"DISPLAY_COMPARE" => "N",
		"SHOW_OLD_PRICE" => "N",
		"PRICE_CODE" => array(
			0 => "BASE",
		),
		"SHOW_PRICE_COUNT" => "1",
		"PRICE_VAT_INCLUDE" => "Y",
		"CONVERT_CURRENCY" => "N",
		"BASKET_URL" => "/personal/cart/",
		"ACTION_VARIABLE" => "action",
		"PRODUCT_ID_VARIABLE" => "id",
		"PRODUCT_QUANTITY_VARIABLE" => "quantity",
		"ADD_PROPERTIES_TO_BASKET" => "Y",
		"PRODUCT_PROPS_VARIABLE" => "prop",
		"PARTIAL_PRODUCT_PROPERTIES" => "N",
		"USE_PRODUCT_QUANTITY" => "N",
		"SHOW_PRODUCTS_2" => "Y",
		"CART_PROPERTIES_2" => array(
			0 => "BRAND_REF",
			1 => "NEWPRODUCT",
			2 => "SALELEADER",
			3 => "",
		),
		"ADDITIONAL_PICT_PROP_2" => "MORE_PHOTO",
		"LABEL_PROP_2" => "SALELEADER",
		"CART_PROPERTIES_3" => array(
			0 => "COLOR_REF",
			1 => "SIZES_SHOES",
			2 => "SIZES_CLOTHES",
			3 => "",
		),
		"ADDITIONAL_PICT_PROP_3" => "MORE_PHOTO",
		"OFFER_TREE_PROPS_3" => array(
			0 => "COLOR_REF",
			1 => "SIZES_SHOES",
			2 => "SIZES_CLOTHES",
		),
		"AJAX_OPTION_ADDITIONAL" => ""
	)
);?>
<?require($_SERVER["DOCUMENT_ROOT"]."/bitrix/footer.php");?>
Еще вся эта ересь безбожно терзает БД. 
А если глянуть ядро - то там несмотря на всякие придуманные штуки типа пространств имен, трейтов и т.п. до сих пор глобальные переменные и куча констант. Есть классы, методы в которых непонятно зачем оборачивают суперглобальные массивы. В общем смотрите сами, это чисто мое мнение и я не собираюсь работать с битриксом, чего и вам желаю

Худший ответ:
Я вспоминаю про битрикс, как про страшный сон после того, как перешёл на Drupal. Эта CMS пользуется большой популярностью на западе. С навыками программирования в Drupal API не сложно разобраться и на нём можно расширять сайт как угодно.